Skill 5D
Estimate Sums: Rounding to nearest 10

Rounding is typically done to the largest place value in a number, however, here we want the student to first round each number to the nearest ten (the middle number). Therefore, the problem should be changed to 220 + 370 when rounding to the tens place and the answer would be 590. Students should eventually reach the point that they can do this type of problem mentally.

Round each number to the nearest ten.  Then add to estimate the sum.

+ 369