Missing One-Digit Numbers

Lucas is at his town’s winter carnival. He wants to find missing numbers as he walks around. Can you help him find missing numbers?

The missing number we want to find is an addend. We will use one addend and the sum to help us find it. Because we know the sum (the total number) and the addend (a part), we can subtract the addend from the sum to find the missing number!

That is because addition and subtraction are opposite operations! Then, we can use addition to check our work. Let’s get started!

Lucas sees 3 horses on the merry-go-round. He knows there are 6 horses in all. That’s a missing number plus 3 equals 6! We need to subtract to find the missing number. 6 is the sum. It goes first in the subtraction sentence. 3 is the addend we know. We will take away 3 from 6. What is 6 minus 3?

3! Is 3 the correct missing number?

We need to add to find out! Let’s add the addend we know and the missing number to see if we get the correct sum. What is 3 plus 3?

6! 6 is the sum we started with. 3 is the correct missing number!

Look at the roller coaster! Lucas sees 5 cars on the roller coaster. He knows there are 9 cars in all. That’s 5 plus a missing number equals 9! What do we do to find the missing number?

Subtract! Which number goes first in the subtraction sentence?

9! 9 is the sum. Which number are we taking away?

5! 5 is the addend we know. What is 9 minus 5?

4! Now we need to add 4 plus 5 to make sure we get 9. Does 5 plus 4 equal 9?

Yes! 4 is the correct missing number!

Lucas wants to count the balloons before he goes home. He counts 2 of them. Lucas knows there are 10 balloons in all. What is the missing number?

8! 10 minus 2 equals 8. Is 8 the correct missing number?

Yes! 2 plus 8 equals 10. 8 is the correct missing number!

Lucas had a great time at the fair! Thank you for your help finding the missing numbers!