Round to the nearest hundred. See Example 7. 1,845 Example 7. Round each number t...

Round to the nearest hundred. See Example 7.

1,845

Example 7.

Round each number to the nearest hundred:

a. 18,349 b. 7,960

Strategy We will find the rounding digit in the hundreds column and the test digit in the tens column.

Why To round to the nearest hundred, the digit in the hundreds column is the rounding digit and the digit in the tens column is the test digit.

Solution

a. First, we find the rounding digit in the hundreds column, which is 3. Then we look at the test digit 4 to the right of 3 in the tens column. Because 4 < 5, we round down and leave the 3 in the hundreds column. We then replace the two rightmost digits with 0’s.

Thus, 18,349 rounded to the nearest hundred is 18,300.

b. First, we find the rounding digit in the hundreds column, which is 9. Then we look at the test digit 6 to the right of 9. Because 6 is 5 or greater, we round up and increase 9 in the hundreds column by 1. Since the 9 in the hundreds column represents 900, increasing 9 by 1 represents increasing 900 to 1,000. Thus, we replace the 9 with a 0 and add 1 to the 7 in the thousands column. Finally, we replace the two rightmost digits with 0’s.