Rounding Whole Number & Decimals

1. Rounding Whole Number & Decimals

2. Rounding & Estimating • In our everyday lives we do not always need exact numbers or exact calculations. • We often use estimations that we get by rounding off numbers

3. A marine biologist estimates that there are 3 000 000 jack-fish in a lake You estimate that your total grocery bill will be $75 before you get to the check out You parents estimate your vacation expenses before you go on vacation as shown on the next slide Examples

4. Expected Vacation Expenses for a One Week Period TOTAL = $1750 (approximately) It would be impossible to calculate the actual cost before the trip, so you use estimates.

5. To Round… (write this as a note in your notebook!) • Look at the digit to the right of the place to which you are rounding • If the digit is 5 or greater, add 1 to the place digit • If the digit is less than 5, leave the place digit as is • Change all the digits to the right of the place digit to 0.

6. Round to nearest hundred • Is the number in the tens column 5 or greater? • Yes • Change the 3 in the hundreds column to a 4 and the remaining numbers become 0s. • 1 342 400.0000 or 1 342 400

7. Practice • http://www.funbrain.com/tens/index.html • Practice • http://www.aaastudy.com/

8. Today’s Work