You use addition and subtraction all the time in your everyday life, whether you are counting loose change or figuring out how many apples are left for you to eat. It is important to be able to solve addition and subtraction problems quickly. One way to do this is to use number families. Number families help you learn addition and subtraction facts about numbers.
Number families are made up of two or three numbers. When you look at a number family, there are several things you know about those numbers. In each number family, there are either two lesser (smaller) numbers and one greatest (larger) number or one lesser number and one greater number. If you add the lesser numbers together, the answer is the greatest number. When you have one lesser number, the number is both addends (numbers added together)-for example, 4 + 4 = 8 and 8 - 4 = 4.
Suppose a number family has the numbers 2, 4, and 6. You know that 2 + 4 = 6. The numbers 2 and 4 are the lesser numbers, and 6 is the greatest number. When you know how number families work, you can figure out each number in a number family even if you aren't shown all three numbers.
Let's look at another number family-3, 5, and 8. This number family tells you that 3 + 5 = 8. The two lesser numbers, when added together, equal the greatest number.
