Question

Give a rough estimate ( by rounding off to the nearest hundred ) and also a closer estimate ( by rounding off to nearest tens ) : $438+332+4215$

Answer 1

Step 1 : By rounding off to nearest hundred

$438$round off to $400$

$332$round off to $300$

$4215$ round off to $4200$

Sum $=400+300+4200$

$=4900$

Step 2 : By rounding off to nearest tens

$438$ round off to $440$

$332$ round off to $330$

$4215$ round off to $4220$

Sum $=440+330+4220$

$=4990$

Estimated sum to nearest hundred is $4900$ and to nearest tens is $4900$ .