Estimation / approximation / rounding

Estimating is the ability to solve number problems in quickly and/or in your head.  We estimate a lot in our daily lives.

The key skill to estimate is rounding.

When rounding remember:

1.  Identify the digit to be rounded and identify the digit to the right of it.

2.  If the digit is 5,6,7,8, or 9  then change the digit to be rounded, one number higher.

    If the digit is 4, 3, 2, 1 or 0 then do not change the digit to be rounded-- it stays the same.

3.  All other digits should be changed to zero.


2,564 is rounded to 3,000

2,564 round to the last digit

2 is the digit to be rounded

5 is the digit to the right.

It is 5 therefore 2 changes to 3