Decimals, like fractions, can name a part of a whole. Decimals are numbers that contain a decimal point such as 1.5, 2.83 and 0.2. When we write numbers, we use a system called base 10. In base 10, the first number to the left of the decimal point represents the number of ones; the second number represents the number of tens; the third number represents the number of hundreds, and so on.

The place values can be explained using the following example.

Notice that as you move to the right, each place value is 10 times less that the one before it. You need to understand this to work with decimals. If you continue the pattern of dividing the previous place value (the one on the left) by 10, then the numbers to the right of the decimal represent the number of tenths (0.1), hundredths (0.01), thousandths (0.001), and so on.

As you moved to the right, you divided by 10, therefore 8 tenths can be written as 0.8, as shown by the division 8 ÷ 10.

In the above diagram, there are 100 squares to equal the whole region. Therefore each square represents one one- hundredth or 0.01 of the region. One row has 10 squares, so it represents ten-hundredths or one-tenth or 0.10 or 0.1 of the region. If you shade in 30 blocks, you have a fraction of 30 hundredths that would be shown as a decimal to the hundredths place and would be written as 0.30. As an example, you can look at money to show the relationship between decimals and fractions. The cent part is written to the right of the decimal point.