Fourth Grade Math: Rounding Numbers

Rounding in Fourth Grade

Place Values

Each digit in a whole number has a place value, and the farther to the left in a number the digit is, the larger its place value. The first digit on the right side of a whole number is in the ones place, and it tells you how many ones the number has. For instance, in the number 5,678, the eight is in the ones place.

The seven is in the tens place, which means that 5,678 has seven tens. The six in the hundreds place tells you that 5,678 has six hundreds, and the five, which is in the thousands place, represents five thousands. The number can be broken down like this:

5,000 + 600 + 70 + 8

Each of these individual numbers can be broken down even further. For instance, 5,000 = 1,000 + 1,000 + 1,000 + 1,000 + 1,000 and 70 = 10 + 10 + 10 + 10 + 10 + 10 + 10. Thus, place value tells you how many of a particular number a larger number contains.

Rounding

Now that you're clear on how place values work, you can use this knowledge to round numbers. First, identify the place you're rounding to. For example, if you're rounding 5,678 to the nearest thousand, the answer will be different than if you're rounding it to the nearest ten.

Once you've found the digit you're rounding to (let's say it's the hundreds digit), you'll need to look at the next digit to its right (the tens digit). If this digit is five or higher, you'll be rounding up. This means you'll add one to the hundreds digit, and change all of the numbers after it (to the right) to zero. For instance, if you rounded 4,567 to the nearest hundred, the answer would be 4,600.

If the tens digit is four or lower, you'll round the hundreds digit down, which means you'll keep it the same and change the numbers after it to zeros. For example, if you round 1,234 to the nearest hundred, the answer will be 1,200.

Practice Problems

Round the following numbers to the place specified in each question.

1. Round 432 to the nearest ten.
2. Round 1,876 to the nearest hundred.
3. Round 4,321 to the nearest thousand.

Answer Key

1. Since two is less than five, you'll round 432 down to 430.
2. Since seven is equal to five or greater, you'll round 1,876 up to 1,900.
3. The number three is less than five, so you'll round 4,321 down to 4,000.