Decimal fractions (other)

Decimal fractions are rational numbers that can be written with denominators of the form $10^n$ for some integer $n \geq 0$. Any terminating decimal is a decimal fraction. Decimal fractions can be written in several equivalent forms (e.g., $0.5 = 0.50 = 0.500$). Not all fractions are decimal fractions; for example, $\frac{1}{3}$ cannot be written exactly as a decimal fraction.

Important properties

• Decimal fractions always have denominators that are powers of ten.

• Every terminating decimal is a decimal fraction.

• Decimal fractions can be easily added, subtracted, multiplied, and divided by aligning decimal points.

• Some decimals are repeating and cannot be written as decimal fractions (e.g., $0.333\ldots$).