Ask Dr. Math

Rounding Numbers

Rounding Numbers

You can read about Rounding Numbers in the Dr. Math FAQ.

Rounding Decimals

Can you explain how to round decimals?

Rounding to Whole Numbers

How do you round to the nearest whole number?

Rounding Fractions to the Nearest Half or Whole

How do you round fractions to the nearest half or whole?

Rounding 3.445 to the Tenths Place

In order to round 3.445 to the tenths place, shouldn't it first be rounded to 3.45, then to 3.5?

Rounding Decimals: Even/Odd Issues

When do you round down, and when do you round up?)

The rule:

To "round to the nearest," look at the digit to the immediate right of the digit you will round to, and

If the digit to the right of your rounding digit is a five or greater (5 through 9), round up (add 1 to the digit you are rounding and drop all the digits to the right, replacing them with zeros);

If the digit to the right of your rounding digit is less than 5 (0 through 4), round down (drop all digits to the right of the digit you are rounding, replacing them with zeros).

Examples:

Rounding 361 to the nearest ten:

The digit in the tens place is 6, so we look at the digit to the right of it (1). That digit is less than 5, so we drop it and replace it with a zero. 361 rounded to the nearest 10 is 360, which is a multiple of 10.

Rounding 361 to the nearest hundred:

The digit in the hundreds place is 3, so we look at the digit to the right of it (6). That digit is 5 or greater, so we add 1 to the digit we are rounding and drop all the digits to the right, replacing them with zeros. 361 rounded to the nearest 100 is 400, which is a multiple of 100.

Rounding .361 to the nearest tenth:

The digit in the tenths place is 3, so we look at the digit to the right of it (6). That digit is 5 or greater, so we add 1 to the digit we are rounding and drop all the digits to the right. .361 rounded to the nearest tenth is .4

Rounding .361 to the nearest hundredth:

The digit in the hundredths place is 6, so we look at the digit to the right of it (1). That digit is less than 5, so we drop it. .361 rounded to the nearest hundredth is .36