4-8 Rounding

Rounding numbers is useful when you don't need to know the exact value of a number.  For example; if your mother asks you to bring about a dozen apples to the house and you know your bucket carries about a dozen apples, you might just fill the bucket and bring it to the house.  You'll be rounding the number 12.

When rounding a number, you need to decide whether to round the number up or down.

For example; if you round the following numbers to the tens place value, 16 would round to 20 and the number 14 would round to 10.

When you are asked to round the number 196 to the nearest hundred, you look at the hundreds place value and see a 1.  Next you look at the tens place value and see a 9.  The digit 9 is greater than 5, so you decide to round 196 up to 200.

When you are asked to round the number 146 to the nearest hundred, you look at the hundreds place value and see a 1.  Next you look at the tens place value and see a 4.  The digit 4 is less than 5, so you decide to round 146 down to 100.

To decide which way to round, always look at the place value to the right of the place value you are rounding.

If the digit to the right of your place value is 4 or less, you round down.  If the digit is 5 or more, you round up because the number is half way or greater.

Round the following numbers to the hundreds place value.

198	112	578
945	321	271
467	299	798
323	901	651
861	249	147

Round the following numbers to the thousands place value.

1,293	1,999
1,678	7,896
2,391	3,799
8,765	9,991
1,199	4,989

Round the following numbers to the ten thousands place value.

89,999	12,832
56,923	93,995
45,345	44,999

Round the following numbers to the hundred thousands place value.

999,201	790,000
140,999	345,981
678,234	555,001

Round the following numbers to the millions place value.

1,223,435	8,924,986
3,459,254	7,897,923
2,459,985	5,543,123