Question

Give a rough estimate (by rounding off to nearest hundreds) and also a closer estimate
(by rounding off to nearest tens):
439 + 334 + 4317

Answer 1

By rounding off to nearest hundreds, the rough estimate of their sum will be:

$\begin{array}{cc}\text{439 round off to}& =400\\ \text{334 round off to}& =300\\ \text{4317 round off to}& =4300\\ \text{Estimated sum}& =5000\end{array}$

By rounding off to nearest tens

$\begin{array}{cc}\text{439 round off to}& =440\\ \text{334 round off to}& =330\\ \text{4317 round off to}& =4320\\ \text{Estimated sum}& =5090\end{array}$