WHOLE NUMBERS – ROUNDING

Concept: Use rounding to make difficult calculations easier to perform, especially when you do not need exact numbers in your calculations.

Steps for Whole Number Rounding

Step 1 | Find the digit you want to round to. Call it the target digit.
Step 2 | Look at the digit to the right of the target digit.
Step 3 | If the digit to the right of the target digit is 5 or more, add 1 to the target digit. If the digit to the right of the target digit is less than 5, do not change the target digit.
Step 4 | In either case, change all digits to the right of the target digit to zeros.

Example Round 31,338,180 to the nearest hundred

Step 1 | Find the digit you want to round to. Call it the target digit. In this case we are targeting the hundreds digit which is a 1 in 31,338,180. | 31,338,1 80
Step 2 | Look at the digit to the right of the target digit. That digit is an 8. | 31,338,1 8 0
Step 3 | If the digit to the right of the target digit is a 5 or more, add 1 to the target digit. 8 is more than 5, so we will add 1 to the target digit. Our target digit is now a 2. (If the digit to the right of the target digit had been less than a 5, we would not have changed the target digit.) | 31,338,2 8 0
Step 4 | In either case, change all digits to the right of the target digit to zeros. 31,338,180 rounded to the nearest hundred is 31,338,200. | 31,338,2 00