8th Grade · The Number System
Terminating Decimal
8.NS.A.1
Definition
A decimal that ends after a finite number of digits. A fraction terminates when its denominator (in lowest terms) has only 2s and 5s as prime factors.
Examples
- 1 ÷ 4 = 0.25, stopping after 2 places.
- 1/3 = 0.333... never stops, since 3 isn't a factor of 2 or 5.
Key rule
Check the denominator's prime factors — only 2s and 5s mean it terminates.
Memory hook
It stops, because the denominator only has 2s and 5s.