Question

Becky added 273+416 and got 688.Then she checked her answer by adding 688+416.What error did Becky make?Was the sum she found for the original problem correct?Explain.

Answer 1

273+416 will give you the sum of 688.
so you take your answer and subtract it from the previous question.
either way you should get the other number to the equation (for example)
688-416=273
or
688-273=416
to check her addition work she should've subtracted her answer from a previous number she used in her addition problem.

Answer 2

You were post to -416 and get 273