Maria Miller
Math Mammoth Division 1 is a worktext that covers the concept of division finding whole-number quotients within 0-100 (essentially the basic division facts) and bar graphs and pictographs. It is most suitable for third grade after the student knows the multiplication tables.The approach taken here to teach division facts is to simply base them on the multiplication tables and not to teach them as a separate set of facts to memorize. This is very efficient and works well when the student knows the times tables. Several lessons in the book focus on this basic concept that division problems can be solved by thinking of multiplication.There are basically two ways to interpret division and thus to illustrate it with concrete objects. The first way has to do with grouping. The problem 12 ÷ 3 is interpreted as 'How many groups of three items can you make out of 12 items?' This is also called measurement division.The second way to interpret division is equal sharing: we divide or share items equally between people or other items. For example the problem 12 ÷ 3 can be interpreted as 'If you share 12 bananas equally between 3 people how many bananas does each one get?'Both of these interpretations of division are important to understand so that the student can solve real-life and mathematical problems involving division.We also study division by zero. In that lesson students should recognize that division by zero 'does not work.' The latter part of the book deals with bar graphs and pictographs. Earlier (in 2nd grade) students have drawn pictographs and bar graphs with single-unit scale. Now they draw scaled pictographs and bar graphs from the given data choosing the scale or how many items one block in the bar graph or one picture in the pictograph signifies. This process provides practice in using both division and multiplication.This book will be relatively easy for students who have mastered the multiplication tables since division facts are just multiplication tables 'backwards'. So students can focus on another important skill: recognizing real-life situations in word problems that mathematically relate to either division or multiplication. This is very important to master so that the student can later on translate more complex situations into equations (modeling with mathematics).You can find free videos covering topics of this book at https://www.mathmammoth.com/videos/ (choose 3rd grade then division).The answer key is appended.
