Decimal place values are the numbers to the right of the decimal point. Let's explain the different names for each place value and demonstrate how to round decimal place values.
Defining Different Decimal Place Values
The decimal place value chart below shows a decimal number in its expanded form. It shows where the tenths place, hundredths place, thousandths place, and ten-thousandths place lie within the decimal number:
As you can see, the first digit after the decimal is called tens place. There is no ones place value in decimals. The whole number part, which is the value to the left of the decimal point, is considered the ones place.
Rounding Decimal Place Values
Now that we know the names of each place value, let's learn how to round decimal place values by using the given number below:
This decimal number has a hundreds place value, but we want to round to the tens place. To do this, we need to look at whether the hundreds place value of 7 means we should round up or down.
Any time the decimal place value is 5 or larger, we must round up. When the place value is 4 or lower, we must round down. Since the value of 7 is larger than 5, we will round up:
Since we rounded up, the tens place value increased by one and went from 8 to 9. If we had rounded down, the value in the tens place would have stayed the same.
Let's use the following practice problems to demonstrate rounding decimal place values:
Notice that whenever the last digit on the right was less than 5, we rounded down and the value to the left stayed the same. But when the last number was higher than 5, we rounded the value to its left up to the next whole number.
Rounding Decimal Place Values
Remember, look to the last listed decimal to round up the value on its left.
Knowing the names of each decimal place value and how to round them up or down will help you solve all kinds of math problems, like converting fractions into numbers.