Use compatible numbers to estimate each difference.
Why did you post an incomplete problem?
To use compatible numbers to estimate the difference between two numbers, you round the numbers to the nearest compatible numbers and then subtract them. Compatible numbers are numbers that are easy to work with mentally because they are close to the original numbers and have known relationships.
Here are the steps to estimate the difference using compatible numbers:
1. Identify the two numbers that you want to find the difference between.
2. Look for compatible numbers that are close to the original numbers. For example, if you have the numbers 37 and 21, you can round them to 40 and 20, which are compatible numbers.
3. Subtract the compatible numbers. Using the rounded numbers 40 and 20, you would subtract 20 from 40, giving you an estimated difference of 20.
So, to estimate the difference between two numbers using compatible numbers, round the numbers to compatible numbers and then subtract them.