**Rounding Whole Numbers**

- Digits below 5 round down, while digits above 4 round up. Here are some examples. Be careful when the digit to the left of the last digit rounded is 9. The digit in

**bold**determines whether to go up or down.

- Round to the nearest whole number: 45.
**3**1 to 45 – 45.**5**to 46 – 59.**8**8 to 60 - Round to the nearest ten: 4
**5**.31 to 50 – 4**4**.89 to 40 – 59**9**.88 to 600 - Round to the nearest hundred: 4
**8**9 to 500 – 4**4**9 to 400 – 59**9**8 to 6000

**Rounding Decimal Numbers**

- The same applies about going up or down and the digit 9. The digit in

**bold**determines whether to go up or down. Here are some examples.

- Round to the nearest tenth: 6.3
**4**9 to 6.3 – 6.3**8**2 to 6.4 – 5.9**9**to 6.0 - Round to the nearest hundredth: 6.34
**9**to 6.35 – 6.38**2**to 6.38 – 5.99**6**6 to 6.00 - Round to the nearest thousandth: .401
**9**to .402 – .753**1**2 to .753 – .899**9**15 to .900

**Scientific Notation**

- This is used with very large whole numbers and very small decimal numbers. The first number is at least 1, but less than 10. It may have one or more digits to the right of the decimal. This is followed by an

**x**sign. This is followed by a power of 10. Here are some examples.

- 93,000,000 = 9.3 x 10
^{7}(There are 7 digits to the right of the**decimal**.) - 258,600,000,000 = 2.586 x 10
^{11}(There are 11 digits to the right of the**decimal**.) - 0004 = 4 x 10
^{-4}(There are 4 digits to the left of the**decimal**. Note the minus sign.) - .000000056 = 5.6 x 10
^{-8}(There are 8 digits to the left of the**decimal**. Note the minus sign.)