Compatible numbers is used to find estimate to a sum. The numbers are chosen because its 'simplicity' when they are multiplied, divided, added or subtracted.
Estimate one:
We can decrease the value 1322 to 1320 and 18 to 15
Then do the sum = 1320÷15 = 88
This estimate is not far from the actual answer 1322÷18 = 73.44..
Estimate two:
We can increase 1322 to 1330 and 18 to 20
Then do the sum 1330÷20=66.50
This estimate is also not far from the actual answer 73.44...
