Use rounding or compatible numbers to estimate the sum of 790-112

If the number ends in 0, 1, 2, 3 or 4, we are going to round down.

If the number ends in 5, 6, 7, 8 or 9, we are going to round up.

790 would stay the same as a good base number, 112 would become 110. This makes it so both numbers end in 0 and will even out the estimated sum.

790 - 110 = 680

680 would be a good estimated sum.

It is 678 hope that's what you meedsed