21 + 34 = 55 but I don't get the question.
The instructions are to round to the each number to the greatest place then add
"Rounding to the greatest place" still is confusing to me. Rounding to the tens will be 60, to the hundreds will be 100. It seems to me that to the greatest place might mean to the thousands or ten thousands or any of a number of other values picked out of a hat. I'm sorry to be so picky but I think the instructions need to be clarified. Thanks for using Jiskha.
54 + 53
First you add 21+34 which is 55.Then you round up to the nearest ten,which would give you 60.So 60 is the answer.
I'd do it this way:
Rounding 21 to 20 and 34 to 35. 20 + 35 = 55