Write the missing number to make this number sentence correct. Nine plus seven take away what equals 12?
The number nine is one less than 10. To help us add seven to nine quickly, we could break seven apart into one and six. First, we can add nine plus one which gives us 10. Now, we can add the six. 10 plus six is 16. Nine plus seven is 16. What do we need to take away from 16 to give us 12? 16 take away four equals 12.
Nine plus seven is 16 take away four equals 12. So, nine plus seven minus four is equal to 12. The missing number is number four.