Test: Decimal numbers

Decimal numbers

In a decimal number, the decimal point separates the whole-number part from the fractional part. The first digit after the point represents tenths and the second represents hundredths. For example, 0.37 is 3 tenths and 7 hundredths, or 37/100.

Comparison and operations

To compare decimals, compare whole-number parts first, followed by tenths, hundredths and later places. Zeros may be added at the end without changing the value: 0.5 = 0.50. For addition and subtraction, align the decimal points vertically.

A common mistake is to assume that a decimal with more digits is always greater. For example, 0.8 is greater than 0.75 because 8 tenths equal 80 hundredths. Place-value reasoning and estimation provide useful checks.