CHAPTER 1 Whole Numbers 3
- Thirty-three billion, six hundred five million, four hundred ninety-
three thousand, six hundred
Rounding Numbers
Many times it is not necessary to use an exact number. In this case, an
approximate number can be used. Approximations can be obtained by
rounding numbers. All numbers can be rounded to specific place values.
To round a number to a specific place value, first locate that place value digit
in the number. If the digit to the right of the specific place value digit is 0, 1, 2,
3, or 4, the place value digit remains the same. If the digit to the right of the
specific place value digit is 5, 6, 7, 8, or 9, add one to the specific place value
digit. All digits to the right of the specific place value digit are changed to zeros.
EXAMPLE
Round 3,261 to the nearest hundred.
SOLUTION
We are rounding to the hundreds place, which is the digit 2. Since the digit to
the right of the 2 is 6, add 1 to 2 to get 3. Change all digits to the right to
zeros. Hence 3,261 rounded to the nearest hundred is 3,300.
EXAMPLE
Round 38,245 to the nearest thousand.
SOLUTION
We are rounding to the thousands place, which is the digit 8. Since the digit
to the right of the 8 is 2, the 8 stays the same. Change all digits to the right of
8 to zeros. Hence 38,245 rounded to the nearest thousand is 38,000.
EXAMPLE
Round 398,261 to the nearest ten thousand.
SOLUTION
We are rounding to the ten thousands place, which is the digit 9. Since the
digit to the right of the 9 is 8, the 9 becomes a 10. Then we write the 0 and add
the 1 to the next digit. The 3 then becomes a 4. Hence the answer is 400,000.
PRACTICE
- Round 3,725 to the nearest thousand.