question_answer 17)

                Estimate each of the following using general rule. (a) 730 + 998                       (b) 796 ? 314                      (c) 12,904 + 2888               (d) 28,292 ? 21,496

Answer:

                (a) 730 + 998 \[\because \] 730 \[\to \] 700     [rounding off to nearest hundreds] 998 \[\to \] 1000               [rounding off to nearest hundreds] \[\therefore \] Estimated sum = 700 + 1000 = 1700 (b) 796 ? 314 \[\because \] 796 \[\to \] 800 [rounding off to nearest hundreds] 314\[\to \]300 (rounding off to nearest hundreds] \[\therefore \]Estimated difference = 800 ? 300 = 500 (c) 12,904 + 2888 \[\because \] 12904 \[\to \] 13000            [rounding off to nearest thousands] 2888 \[\to \] 3000             [rounding off to nearest thousands] \[\therefore \] Estimated sum = 13000 + 3000 =16000 (d) 28,292 ? 21,496 \[\because \] 28,292 ? 28,000                     [rounding off to nearest thousands] 21,496 \[\to \] 21,000     [rounding off to nearest thousands] \[\therefore \] Estimated difference = 28000 ? 21000 = 7000