Josiah subtracts 337 from 600 and writes the following:
600 minus 300 is 300. Then I can subtract 40 more and get 260. But I should have only subtracted 37 more, so I'll add 3 back to my difference to get 263.
Which mental math strategy did Josiah use?
A.
Associative Property
B.
Breaking Apart
C.
Compensation
D.
Counting On
Break apart
The mental math strategy that Josiah used is Compensation.
Compensation is a strategy where you adjust the numbers in a calculation to make the mental math easier. In this case, Josiah found that subtracting 337 from 600 was a bit difficult, so he used the compensation strategy to make the calculation easier.
He started by breaking apart 600 into 300 and another 300. 600 minus 300 is 300. Then he subtracted 40 more from the remaining 300 to get 260. But he realized that he had actually subtracted 37 more than he should have, so he added 3 back to his difference to get 263.
By using compensation, Josiah adjusted the numbers in the calculation to simplify the mental math process and arrive at the correct answer.