• # question_answer 18)                 Give a rough estimate (by rounding off to nearest hundreds) and also a closer estimate (by rounding off to nearest tens). (a) 439 + 334 + 4317                                                         (b) 1,08,734 ? 47,599 (c) 8325 ? 491                                                                     (d) 4,89,348 ? 48,365

(a) We have, 439 + 334 + 4317 $\because$ \left. \begin{align} & 439\to 400 \\ & 334\to 300 \\ & 4317\to 4300 \\ \end{align} \right\}      [rounding off to nearest hundreds] $\therefore$ Rough estimate = 439 + 334 + 4317 = 400 + 300 + 4300 = 5000 Again, \left. \begin{align} & 439\to 440 \\ & 334\to 330 \\ & 4317\to 4320 \\ \end{align} \right\} [rounding off to nearest tens and closer estimate = 439 + 334 + 4317 = 440 + 330 + 4320 = 5090 (b) We have, 1,08,734 ? 47599 $\because$ \left. \begin{align} & 1,08,734\to 1,08,700 \\ & 47,599\to 47,600 \\ \end{align} \right\}      [rounding off to nearest hundreds] $\therefore$ Rough estimate = 1,08,734 ? 47,599 = 1,08,700 ? 47,600 = 61,100 Again, \left. \begin{align} & 1,08,734\to 1,08,730 \\ & 47,599\to 47,600 \\ \end{align} \right\}      [rounding off to nearest tens] and closer estimate = 1,08,734 ? 47,599 = 1,08,730 ? 47,600 = 61,130 (c) We have, 8325 ? 491 $\because$ \left. \begin{align} & 8325\to 8300 \\ & 491\to 500 \\ \end{align} \right\}                      [rounding off to nearest hundreds] $\therefore$ Rough estimate = 8325 ? 491 = 8300 ? 500 = 7800 Again, \left. \begin{align} & 8325\to 8330 \\ & 491\to 490 \\ \end{align} \right\}                      [rounding off to nearest tens] and closer estimate = 8325 ? 491 = 8330 ? 490 = 7840 (d) We have, 4,89,348 ? 48,365 $\because$ \left. \begin{align} & 489348\to 4,89,300 \\ & 48,365\to 48,400 \\ \end{align} \right\}      [rounding off to nearest hundreds] $\therefore$ Rough estimate = 439,348 ? 48,365 = 4,89300 ? 48,400 = 4,40,900 Again, \left. \begin{align} & 4,89,348\to 4,89,350 \\ & 48,365\to 48,370 \\ \end{align} \right\}      [rounding off to nearest tens] and closer estimate = 439,348 ? 48365 = 439350 ? 48,370 = 4,40,980