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| 5 minute math activities: 101 Math Activities for Calculating Kids Tracey Ann Schofield, 2001-03-01 Explore math concepts, explore real-world situations, encourage logical thinking, motivate your students. |
| 5 minute math activities: Math Starters Judith A. Muschla, Gary R. Muschla, Erin Muschla, 2013-08-22 A revised edition of the bestselling activities guide for math teachers Now updated with new math activities for computers and mobile devices—and now organized by the Common Core State Standards—this book includes more than 650 ready-to-use math starter activities that get kids quickly focused and working as soon as they enter the classroom. Ideally suited for any math curriculum, these high-interest problems spark involvement in the day's lesson, help students build skills, and allow teachers to handle daily management tasks without wasting valuable instructional time. A newly updated edition of a bestselling title Ideal for math teachers in grades six through twelve Includes more than 650 ready-to-use starter problems |
| 5 minute math activities: Ten-minute Math Cornelia C. Tierney, Susan Jo Russell, 2000 This book originated as part of the K-5 mathematics curriculum, Investigations in Number, Data, and Space as quick explorations woven throughout the program to support each unit. Teachers asked that these activities be assembled in a single, easy-to-access collection, and that is how Ten Minute Math came to be.Whether or not you use Investigations, Ten Minute Math is a valuable resource for ongoing work in three major areas of the elementary mathematics curriculum: Number, Data analysis, and Two- and three dimensional space (geometry).With the activities in these three areas, you can help your students acquire broader mathematical thinking and problem-solving skills. You will also help them increase their strategies for mental calculation, gain confidence in inventing their own approaches for solving problems, and become more fluent in reflecting on and articulating their problem-solving processes. |
| 5 minute math activities: Spectrum Math Workbook, Grade 4 Spectrum, 2014-08-15 Spectrum Math for grade 4 keeps kids at the top of their math game using progressive practice, math in everyday settings, and tests to monitor progress. The math workbook covers multiplication, division, fractions, geometric figures, and preparing for algebra. --A best-selling series for well over 15 years, Spectrum still leads the way because it works. It works for parents who want to give their child a leg up in math. It works for teachers who want their students to meetÑand surpassÑlearning goals. And it works to help children build confidence and advance their skills. No matter what subject or grade, Spectrum provides thorough practice and focused instruction to support student success. |
| 5 minute math activities: 5-Minute Math Problem of the Day for Young Learners Betsy Franco, 2001-09 Add these lively, easy-to-read math problems to each school day and watch students fall in love with math learning as they build essential skills! Covers all the concepts they need to know: addition, subtraction, time, money, measurement, estimation, and so much more. Great for whole class, group, or independent learning. Content is correlated with the NCTM Standards. For use with Grades 1-2. |
| 5 minute math activities: The Time Math Activity Workbook Book 2 Catchpole, 2007-01-01 Introduce students to key mathematical concepts related to time! Expand understanding of concepts such as time to the hour and half hour; time to the nearest five minutes; time to the nearest minute; the passing of time; digital time and clock faces; the twentyfour hour clock; timing activities; and calendar activities. |
| 5 minute math activities: Measurements in Mathematics Activities Workbook Book 3 Willey, 2007-01-01 Challenging investigations allow students to measure with arbitrary units and rulers; use clocks and calendars to measure time; measure perimeters and areas; investigate mass and the balancing of objects; and explore volume and mass. |
| 5 minute math activities: 5-minute Fractions & Decimals Practice Jill Safro, 2011 180 short exercises in ActivInspire (Promethean) for the interactive whiteboard that actively engage students in fractions and decimals practice to sharpen their math skills and prepare them for standardized tests! |
| 5 minute math activities: Math Activities Using Colorful Cut-OutsTM, Grade 3 Joyce Kohfeldt, Johnny Warrick, 2008-08-28 Motivate and engage students in grade 3 with Math Activities Using Colorful Cut-OutsTM. This 112-page book is filled with skills-based, interactive math activities that are fun to use and easy to prepare. It includes more than 40 activities that focus on graphing, measuring, fractions, multiplying, elapsed time, and counting money. The book also includes leveled activities, a skills matrix, an assessment matrix, and reproducible cutouts and aligns with state, national, and Canadian provincial standards. |
| 5 minute math activities: Elementary Mathematics Curriculum Materials Janine T. Remillard, Ok-Kyeong Kim, 2020-03-16 The book presents comparative analyses of five elementary mathematics curriculum programs used in the U.S. from three different perspectives: the mathematical emphasis, the pedagogical approaches, and how authors communicate with teachers. These perspectives comprise a framework for examining what curriculum materials are comprised of, what is involved in reading and interpreting them, and how curriculum authors can and do support teachers in this process. Although the focus of the analysis is 5 programs used at a particular point in time, this framework extends beyond these specific programs and illuminates the complexity of curriculum materials and their role in teaching in general. Our analysis of the mathematical emphasis considers how the mathematics content is presented in each program, in terms of sequencing, the nature of mathematical tasks (cognitive demand and ongoing practice), and the way representations are used. Our analysis of the pedagogical approach examines explicit and implicit messages about how students should interact with mathematics, one another, the teacher, and the textbook around these mathematical ideas, as well as the role of the teacher. In order to examine how curriculum authors support teachers, we analyze how they communicate with teachers and what they communicate about, including the underlying mathematics, noticing student thinking, and rationale for design elements. The volume includes a chapter on curriculum design decisions based on interviews with curriculum authors. |
| 5 minute math activities: The Algebra Teacher's Activity-a-Day, Grades 6-12 Frances McBroom Thompson, Ed.D., 2010-06-08 Fun-filled math problems that put the emphasis on problem-solving strategies and reasoning The Algebra Teacher's Activity-a-Day offers activities for test prep, warm-ups, down time, homework, or just for fun. These unique activities are correlated with national math education standards and emphasize problem-solving strategies and logical reasoning skills. In many of the activities, students are encouraged to communicate their different approaches to other students in the class. Filled with dozens of quick and fun algebra activities that can be used inside and outside the classroom Designed to help students practice problem-solving and algebra skills The activities address a wide range of topics, skills, and ability levels, so teachers can choose whichever best suit the students' needs. |
| 5 minute math activities: Research on Mathematics Textbooks and Teachers’ Resources Lianghuo Fan, Luc Trouche, Chunxia Qi, Sebastian Rezat, Jana Visnovska, 2018-02-13 This book focuses on issues related to mathematics teaching and learning resources, including mathematics textbooks, teacher guides, student learning and assessment materials, and online resources. The book highlights various theoretical and methodological approaches used to study teaching and learning resources, and addresses the areas of resources, teachers, and students at an international level. As for the resources, the book examines the role textbooks and other curricular or learning resources play in mathematics teaching, learning, and assessment. It asks questions such as: Could we consider different types of textbooks and roles they play in teaching and learning? How does the digitalization of information and communication affect these roles? What are defining features of e-textbooks, and how could we characterize the differences between the traditional textbooks and e-textbooks? As for the teachers, the book discusses the relationships between teachers’ individual and collective resources, and the way in which we could model such relationships. Specific questions addressed are: What is the role of teachers in developing textbooks and other teaching and learning materials? What are the relationships between resource designers and users? What are the consequences of these changing roles and relationships for the teaching of mathematics, and for teacher knowledge and professional development? As for the students, the book explores how students, as well as their teachers, interact through resources. It raises and addresses questions such as: What are the effects of modern ICT (particularly internet) on students’ use and the design of resources? How do changing patterns of use and design affect student behaviour, learning, and relationships to the subject of mathematics? |
| 5 minute math activities: Resources in Education , 2001-10 |
| 5 minute math activities: More Minute Math Drills, Grades 1 - 3 Carson-Dellosa Publishing, 2008-02-19 Build students' math fluency with More Minute Math Drills: Addition and Subtraction for grades 1Ð3. This 128-page book includes customizable drill pages for differentiating instruction, number searches, and color-by-number and matching activities. The book supports NCTM and the Common Core State standards and includes reproducible award certificates and answer keys. |
| 5 minute math activities: One Million Children Robert E. Slavin, Nancy A. Madden, 2001 One Million Children describes the `Success for All′ and `Roots & Wings′ programmes in detail, presents the extensive research evaluating them, and discusses the implications of this research for policy and practice. `Success for All′ and `Roots & Wings′ are comprehensive restrucuring programmes for primary schools designed to promote the idea that `all children can learn′. |
| 5 minute math activities: Intermediate Teacher's Math Activities Kit Stephen J. Micklo, 2004-09-24 Grade level: 4, 5, 6, e, i, t. |
| 5 minute math activities: Taking Small Classes One Step Further Jeremy D. Finn, Kenneth K. Wong, 2002-08-01 |
| 5 minute math activities: Distance Learning for Elementary STEM Amanda Thomas, 2022-08-17 This practical guide outlines a vision for online and distance STEM learning at the elementary level, with creative activities based on eight STEM themes. Online and distance learning may sound fairly straightforward. Instead of learning in a classroom setting, students learn at home with the assistance of online resources. But classroom learning does not always translate easily to online settings, particularly at the elementary level where children should be actively engaging in activities, exploration and discussion. From designing a zoo, to learning to garden, to exploring the night sky, you’ll find eight STEM lessons that are creative, hands-on and engaging for elementary learners. Written for teachers and parents, the book unpacks STEM integration across multiple subjects, with connections to the ISTE Standards. The book also includes play-based lessons for young learners, and ideas for innovative design challenges. Each of the eight lessons includes: • An overview of materials, resources, time and supervision needed. • Suggested resources to explore, such as simulations and virtual field trips. • Supplementary learning materials such as questions and quizzes. • Ideas for games and reinforcement. • Hands-on activities and engineering design challenges. • Connections to various content areas as well as children’s books, movies and art to keep the learning going after the lesson is completed. Concluding with a model for designing online and distance STEM learning for elementary-aged children, this book will support teachers and parents in designing the types of resources and learning experiences they need for elementary students’ distance learning. |
| 5 minute math activities: Math Activity Cards for School and Home, Grade 2 Carson-Dellosa Publishing, 2013-01-02 Review and reinforce essential second grade math skills with fun and engaging, standards-based flash-cards. Aligned to Common Core Standards, this book features more than 100 flash cards along with activities for each day of the school week! Activities are designed to complete independently or in group instruction. Activities include sorting, categorizing, and memorizing, as well as games and riddles to engage even the most reluctant learners. |
| 5 minute math activities: Seventh-Grade Math Minutes Doug Stoffel, 2007-12 One Hundred Minutes to Better Basic Skills Help middle-grade students master essential math skills with the motivating, classroom-tested |
| 5 minute math activities: Home Education Masterclass: Math Made Easy Nicole Young, Mathematics is often perceived as a daunting subject, a source of anxiety for both children and adults alike. This book challenges that perception, offering a fresh perspective on math education that emphasizes engagement, understanding, and a growth mindset. Home Education Masterclass: Math Made Easy is designed to equip parents and educators with the tools and techniques to transform math learning from a struggle into an enjoyable and enriching experience. This comprehensive guide provides practical strategies for teaching math at all levels, from basic arithmetic to more advanced topics like algebra and geometry. We’ll explore various teaching methods, catering to diverse learning styles – visual, auditory, and kinesthetic – so that every child can access and understand mathematical concepts. You will find detailed explanations of core mathematical principles, illustrated with real-world examples to make learning more tangible and relatable. Step-by-step instructions for solving problems, along with a variety of engaging activities and games, will make math learning fun and effective. The book also addresses common challenges in math education, such as math anxiety and learning disabilities, offering practical strategies for addressing these issues and creating a supportive learning environment. We'll delve into assessment strategies, emphasizing the importance of formative assessment to track progress and tailor instruction to individual needs. We understand that every child learns differently, and this book provides the flexibility to adapt your teaching approach to suit each child's unique learning style. Ultimately, our goal is to foster a positive and productive learning environment where children develop not only mathematical skills but also a lifelong love of learning. |
| 5 minute math activities: The Time Math Activity Workbook Book 3 Catchpole, 2007-01-01 Introduce students to key mathematical concepts related to time! Challenging activities focus on time to the nearest minute; digital time; time to the nearest second; stopwatch activities; changing time; the passing of time; calendar activities; timetable activities; and time surveys. |
| 5 minute math activities: Children's Competencies Development in the Home Learning Environment Frank Niklas, Caroline Cohrssen, Simone Lehrl, Amy R. Napoli, 2021-08-02 |
| 5 minute math activities: 40 Fun-Tabulous Puzzles for Multiplication, Division, Decimals, Fractions, and More Bob Olenych, 2000-11 The world lies devastated after the massive oil crisis that was described in LAST LIGHT. Human society has more or less entirely broken down and millions lie dead of starvation and disease. There are only one or two beacon communities that have managed to fashion a new way of living.Jenny Sutherland runs one of these groups. Based on a series of decaying offshore oil-rigs - for safety - a few hundred people have rebuilt a semblance of normality in this otherwise dead world.But as her and her people start to explore their surroundings once again, they start to realise not every survivor has the same vision of a better future than their catastrophic past. There are people out there who would take everything they have. War is coming, and the stakes are truly massive... |
| 5 minute math activities: The Grammar Teacher's Activity-a-Day: 180 Ready-to-Use Lessons to Teach Grammar and Usage Jack Umstatter, 2010-04-19 Quick, daily classroom lessons for improving students' grammar and writing skills This must-have resource features 180 practical, ready-to-use grammar and usage lessons and activities–one for each day of the school year. The activities included help students in grades 5-12 to acquire, improve, and expand their grammar skills, and become more adept and confident writers. Veteran educator and best-selling author Jack Umstatter helps teachers to familiarize students with the type of grammar-related content found on standardized local, state, national, and college admissions tests. Includes ready-to-use, yet comprehensive and authoritative activities for use as sponge activities, extra homework, or regular daily lessons Reproducible lessons are designed to be non-intimidating and clear for students Other titles by Umstatter include Grammar Grabbers!, 201 Ready-to-Use Word Games for the English Classroom, Brain Games!, and Got Grammar? Tips for educators on how to best utilize each specific topic or lesson are included for easy classroom instruction. |
| 5 minute math activities: Early mathematics counts Yasmin A Sitabkhan, Linda Platas, 2018-07-23 This occasional paper examines common instructional strategies in early-grade mathematics interventions through a review of studies in classrooms in low- and middle-income countries. Twenty-four studies met the criteria for inclusion, and analyses reveal four sets of instructional strategies for which there is evidence from multiple contexts. Of the 24 studies, 16 involved the use of multiple representations, 10 involved the use of developmental progressions, 6 included supporting student use of explanation and justification, and 5 included integration of informal mathematics. Based on the review, we provide conclusions and recommendations for future research and policy |
| 5 minute math activities: 2 Million Children Robert E. Slavin, Nancy A. Madden, Bette Chambers, Barbara Haxby, 2008-12-05 Based on a program that has benefited over 2 million children, this updated edition outlines steps for school reform and achievement through prevention, intervention, and assessment to promote reading. |
| 5 minute math activities: The Unsinkable Sub Debbie Connolly, Laurie Danley, 2008-09-01 A rich resource that supports a wide range of content areas and curricular materials. Each of 11 theme chapters provide complete instructions and materials for a full day of organized, engaging, theme-based activities. --Back cover. |
| 5 minute math activities: Rethinking Classroom Management Patricia Sequeira Belvel, Maya Marcia Jordan, 2003 Based upon the authors' many years of classroom experience and consulting work this volume is filled with practical, research-based and tested strategies to help teachers create an environment that supports students' sense of self-esteem, influence and autonomy whilst preventing possible conflict. |
| 5 minute math activities: Liberty Mathematics Level a Grd 1 Teacher Manual Wendy Kramer, Teacher Manual, 2005-08-10 Teacher Guide for Liberty Mathematics Workbook A. Designed to give first grade students an introduction to primary mathematics concepts. Topics covered include addition and subtraction facts from 1 18, two-digit addition and subtraction, fractions, calendars, time and money, measurement, and sets. |
| 5 minute math activities: Subtracting Fractions , |
| 5 minute math activities: Everyday Mathematics University of Chicago. School Mathematics Project, 1998 |
| 5 minute math activities: U-Turn Teaching Rich Allen, Jenn Currie, 2012-09-04 Help middle schoolers engage in the classroom before it′s too late! The middle school years mark a critical point in a child′s educational journey. For many educators, these years are the last chance to put in place strong, positive learning patterns. U-Turn Teaching is founded on Rich Allen′s Green Light education strategies, in which every activity is designed to proactively support learning. This book builds on what researchers have discovered about how the adolescent brain learns best, and shows how those discoveries directly relate to effective classroom teaching. Now you can engage all students, even unmotivated ones, and help them make a U-turn by applying these four principles of brain-based learning: Build and maintain trust Create a collaborative community Take a TEAMing approach Prime the positive environment U-Turn Teaching demonstrates how to realistically accomplish these four principles in your classroom. When educators are able to embed positive, efficient, and effective patterns of learning in the middle years, students are far more likely to succeed in high school and beyond! |
| 5 minute math activities: The Math Teacher's Problem-a-Day, Grades 4-8 Judith A. Muschla, Gary R. Muschla, 2008-04-11 From bestselling authors Judith and Gary Muschla, The Math Teacher's Problem-a-Day is a hands-on resource containing 180 handy worksheets, one for each day of the school year, to help students in grades 4-8 acquire the skills needed to master mathematics. These reproducible worksheets are perfect for sponge activities—five-minute challenges to start or end a class period—that can also be used as supplemental lessons, homework, or extra credit. With problems based on the Standards and Focal Points of the National Council of Teachers of Mathematics, the book is designed to give students valuable practice in math skills, using specific activities to enhance critical thinking and boost test scores. The topics covered focus on the core math concepts and skills required for middle school students, including: Numbers and Operations Algebra Geometry Measurement Data Analysis Part of the 5-Minute Fundamentals series, The Math Teacher's Problem-a-Day is an important resource that will help today's students understand more concepts, make connections between branches of mathematics, and apply math skills to a variety of real-life problems. |
| 5 minute math activities: Five Minute Mum: Give Me Five Daisy Upton, 2020-02-06 Ideal for early years to KS1 children who are learning at home. Daisy Upton has two little kids. She loves them - but they drive her mad. So, to try and keep her sanity she started to come up with quick, easy games using stuff from around the house. And @FiveMinuteMum was born. In her first book, she has collected 150+ games that take 5 minutes to set up & 5 minutes to tidy up. From pasta posting to alphabet knock down, it's a recipe book for guilt free parenting! And as Daisy was a teaching assistant, your little ones will be learning while they play! What could be better? GIVE ME FIVE is the perfect companion for anyone who wants five minutes peace. Also available: Five Minute Mum: Time For School Five Minute Mum: On the Go I love Five Minute Mum. She's managed to come up with a huge array of activities for kids that are fun and educational yet don't require an Art degree or Diploma in Patience to execute.Sarah Turner, aka Unmumsy Mum |
| 5 minute math activities: Navigating the Social World Jeanette L. McAfee, 2002 Because of its unique focus on teaching the critical social skills that autistic children lack, this book has been cited by Library Journal as Essential to All Collections. |
| 5 minute math activities: Computer Activities Across the Curriculum Heidi Stirm, 2001 |
| 5 minute math activities: Measurement Benchmarks , 2006 |
| 5 minute math activities: Differentiating Math Instruction William N. Bender, 2005-05-18 This exciting and unique book presents practical, immediately applicable ideas for differentiating instruction in maths in the elementary classroom. It explains in detail the process of differentiation in maths, beginning with lesson planning, through implementation of a wide variety of research-proven instructional strategies and tactics. The ′Ideas from Teachers′ feature, located in various chapters, includes instructional tactics provided by teachers that exemplify the differentiation process. Also included are the ′To Ten Tactics′ lists which provide simple, immediately applicable tactics that can be easily implemented in almost every classroom. |
| 5 minute math activities: Functional Communication Training for Problem Behavior Joe Reichle, David P. Wacker, 2017-04-26 Children and adolescents with moderate and severe disabilities often have communication challenges that lead them to use problem behavior to convey their desires. This is the most comprehensive contemporary volume on functional communication training (FCT)--the individualized instructional approach that teaches a child socially acceptable communicative alternatives to aggression, tantrums, self-injury, and other unconventional behaviors. The expert authors provide accessible, empirically based guidelines for implementing FCT, and tips for overcoming obstacles. Grounded in the principles of applied behavior analysis, the book includes detailed strategies for developing a support plan, together with illustrative case examples. |
万分之五怎么写？0.5% 0.5‰ 5‰ ？到底是那个啊？谢谢
万分之五是千分之0.5，也就是0.05%，但是一般不这样写，不过你也可以这样写，有一种新的表达就是千分之0.5，所以是0.5‰。 千分号就是在百分号的基础上再加一个根据好似的圆圈，如 …
英语的1~12月的缩写是什么？ - 百度知道
5、May无缩写 五月； 6、Jun. June 六月； 7、Jul. July 七月； 8、Aug. August 八月； 9、Sep. September九月； 10、Oct. October 十月； 11、Nov. November 十一月； 12、Dec. …
英文1号到31号日期缩写 - 百度知道
Jun 10, 2022 · 1日：first（1st）、2日：second（2nd）、3日：third（3rd）、4日：fourth（4th）、5日：fifth（5th）、6日：sixth（6th）、7日：seventh（7th ...
上古卷轴5技能点代码是什么-上古卷轴5技能点代码大全_百度知道
Nov 22, 2024 · 上古卷轴5技能点代码是什么呢?在上古卷轴5游戏里，玩家想要升级技能点需要消耗技能点数，因此技能点是相当重要的，那么究竟有什么代码可以帮助大家快速拥有技能点 …
2、4、5、6、8分管，管径分别是多少mm - 百度知道
5、管径的表达方式应符合下列规定： 一般情况下，铸铁管和球墨铸铁管、镀锌钢管、焊接钢管都是用dn来表示的，称为管道的公称直径。 DN20(4分管 ) 4分是指外径吗？
照片的1寸、2寸、5寸、6寸、7寸、8寸、9寸、10寸、12寸、14寸 …
因为它的标准大小是7×5英寸，而一英寸约等谨者于2.54厘米，我们可通过计算得出这个结果。 七寸照片横版、竖版 七寸证件照在300dpi分辨率下的像素尺寸如下：
大乐透的中奖规则 - 百度知道
Aug 19, 2024 · 或者前区5个号码命中2个，后区2个号码命中2个。奖金：15元。追加无奖励。 9、九等奖。中奖规则：前区5个号码命中3个，后区2个号码命中0个。或者前区5个号码命中1 …
I,IV ,III,II,IIV是什么数字. - 百度知道
对应阿拉伯数字，也就是现在国际通用的数字为：Ⅰ是1，Ⅱ是2，Ⅲ是3，Ⅳ是4，Ⅴ是5，Ⅵ是6，Ⅶ是7，Ⅷ是8，Ⅸ是9，Ⅹ是10。 可以通过打开软键盘打出罗马数字。 点击“软键盘”，选 …
月份的英文缩写及全名 - 百度知道
提供月份的英文全名和缩写对照表，帮助用户快速查询和学习。
帮忙翻译下希腊数字 Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ、Ⅵ、Ⅶ、Ⅷ、Ⅸ、Ⅹ …
最古的计数目大概至多到3，为了要设想“4”这个数字，就必须把2和2加起来，5是2加2加1，3这个数字是2加1得来的，大概较晚才出现了用手写的五指表示5这个数字和用双手的十指表示10这 …
万分之五怎么写？0.5% 0.5‰ 5‰ ？到底是那个啊？谢谢
万分之五是千分之0.5，也就是0.05%，但是一般不这样写，不过你也可以这样写，有一种新的表达就是千分之0.5，所以是0.5‰。 千分号就是在百分号的基础上再加一个根据好似的圆圈，如图：‰ 这个就是 …
英语的1~12月的缩写是什么？ - 百度知道
5、May无缩写 五月； 6、Jun. June 六月； 7、Jul. July 七月； 8、Aug. August 八月； 9、Sep. September九月； 10、Oct. October 十月； 11、Nov. November 十一月； 12、Dec. …
英文1号到31号日期缩写 - 百度知道
Jun 10, 2022 · 1日：first（1st）、2日：second（2nd）、3日：third（3rd）、4日：fourth（4th）、5日：fifth（5th）、6日：sixth（6th）、7日：seventh（7th ...
上古卷轴5技能点代码是什么-上古卷轴5技能点代码大全_百度知道
Nov 22, 2024 · 上古卷轴5技能点代码是什么呢?在上古卷轴5游戏里，玩家想要升级技能点需要消耗技能点数，因此技能点是相当重要的，那么究竟有什么代码可以帮助大家快速拥有技能点呢?下面就是上古卷 …
2、4、5、6、8分管，管径分别是多少mm - 百度知道
5、管径的表达方式应符合下列规定： 一般情况下，铸铁管和球墨铸铁管、镀锌钢管、焊接钢管都是用dn来表示的，称为管道的公称直径。 DN20(4分管 ) 4分是指外径吗？
