How to Teach Children Subtraction

Tips for Helping Children Learn Subtraction

Subtraction for Young Children

It can help children if you present subtraction in a specific sequence. In fact, this is good for presenting any new math fact. In each step of the sequence, you first demonstrate and explain. Then give your child the opportunity to copy your demonstration and make it her own.

1. Begin with 3-dimensional objects. Find concrete objects that can be used for counting, such as small blocks, beans, buttons, Cheerios or jacks. Show your child eight blocks, for example, and say you are going to take away three of them. Remove three blocks and ask how many remain.
   
   
2. Next, use 2-dimensional drawings and illustrations. Begin by drawing eight circles on a dry erase board. When you say you are going to take away three of them, cross them out, and ask how many remain.
   
   
3. Lastly, demonstrate with numbers and math symbols. Show your child how to write subtraction sentences (8 - 3 = 5) and problems in the 3-line work format.

Subtraction Facts for Young Children

Once your child learns these concepts and understands subtraction, she needs to learn the facts from 0 - 0 up to 9 - 9. Stories, drawings, songs and games can help here. Cement the facts and speed their recall by using flash cards.

One book that is very helpful in teaching both addition and subtraction math facts is Two Plus Two Is Not Five (Easy Methods to Learn Addition & Subtraction) by Susan R. Greenwald. A good card game for several players is Math War Addition and Subtraction by School Zone Publishing Company. Check your library or teachers' store for other books and games.

Subtraction Using Multiple-Digit Numbers and Decimals

Subtracting numbers with multiple digits is often where students get completely lost. If this is approached slowly - demonstrating step-by-step - most children should have no problem. One approach to subtracting both multiple-digit whole numbers and decimals is regrouping, which is commonly called borrowing.

Subtraction by Regrouping

When you subtract by regrouping, you will be changing the top number. Using 9458 - 6793 to teach regrouping, start by writing the problem in the following manner:

9 thousands + 4 hundreds + 5 tens + 8 ones
- 6 thousands - 7 hundreds - 9 tens - 3 ones

Explain that when the bottom number is larger than the top number, break out one unit of greater value into ten units of the next lower value, and reorganize. Show her that this problem would then be written with the top number as 8 thousands + 13 hundreds + 15 tens + 8 ones; the bottom number will be unchanged. From this point, you can solve the problem. The answer is 2,665.