Using compatible numbers to estimate 83+34

80 + 30

then add

80 + 30=110

then add the numbers you left out

3 + 4 = 7

and you get 117

or you can round up

90 + 40

90 + 40=130

then you subtract the numbers you added on

90 - 83 = 7

40 - 34 = 6

then you add those and subtract from 130 and you get 11Answer here