Decimal place value: FAQ

Decimals are a way of writing numbers that include parts of a whole. They are written with a decimal point to separate the whole number from the fractional part. For example, $2.5$‍ is a decimal number that is equivalent to $2{\displaystyle \frac{1}{2}}$‍.

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We can compare decimals by starting with the whole number parts. If they are different, the larger whole number makes the larger decimal. If the whole number parts are the same, compare the digits after the decimal point from left to right until you find a difference.

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When we compare numbers, we should always start with comparing the largest place value. We can use a place value chart to compare all the numbers.

The greatest place value with different digits is the tenths place.

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We can write decimals like we write whole numbers, in standard, written, or expanded form.

Standard form is the way we typically write decimals, with the whole number to the left of the decimal point and the fractional part to the right. For example: $6.35$‍ is in standard form.

Written form means writing the decimal out in words. For the examples above: $6.35$‍ would be written as "six and thirty-five hundredths."

Expanded form means breaking the decimal down into its individual place values. Using the examples above: $6.35$‍ would be written as $(6\times 1)+(3\times {\displaystyle \frac{1}{10}})+(5\times {\displaystyle \frac{1}{100}})$‍.

Try it yourself with these exercises:

Decimals are used in many places! For example, they are often used to represent currency (like $\mathrm{\$}2.50$‍), measurements (like $5.5$‍ inches), and percentages (like $0.75$‍, which is equivalent to $75\mathrm{\%}$‍).