Question

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

8325 - 491

Answer 1

Rounding off to hundreds, 8325 and 491 may be rounded off to 8300 and 500 respectively.

8300
 -500 
7800

Rounding off to tens, 8325 and 491 may be rounded off to 8330 and 490 respectively.

8330
 -490 
7840