Working with number families is important, because it teaches us how numbers work together. When we know how numbers work together, we can more easily solve problems we come across in our daily lives. Addition and subtraction come up a lot in our everyday lives, so addition and subtraction number families are important for us to learn.
When you are shown a number family, you are given two or three numbers in a certain order. If you have only two numbers, thelesser (smaller) number is both addends (numbers added together). For example, if the numbers are 3 and 6, the addition and subtraction facts are 3 + 3 = 6 and 6 - 3 = 3. The two lesser numbers come before the greatest (larger) number, because adding the lesser numbers together gives you the greatest number. Now that you know this, you can easily find the addition facts in a number family.
When you see a number family, find the lesser numbers. For example, if we have a number family with 5, 6, and 11, the lesser numbers are 5 and 6. The addition facts for this number family are 5 + 6 = 11 and 6 + 5 = 11.
There are also subtraction facts for every number family. To find the subtraction facts, you go the opposite way with the number family. You start with the greatest number and then subtract one of the lesser numbers to get the other lesser number. For example, 11 - 6 = 5 is one of the subtraction facts for this number family. The other subtraction fact is 11 - 5 = 6.
Remember, with addition facts in number families, you add the lesser numbers together. With subtraction facts in number families, you start with the greatest number and subtract one of the lesser numbers.
