Estimate the sum 622+84

the estimate would be 700, the actual answer is 706

Step-by-step explanation:

when estimating, if it is 4 and or below then you have to round down. in this case since, 2 is below 4 (in the tens place) so we round to 620. and this also applies to the 84, since it is 4 and or below, we round to 80. 620 + 80 = 700

620+80 = 700 now we only have 2+4=6, thus: 700+6 = 706