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.
Teach it
Where it is taught, with guided notes, practice, homework, an exit ticket and an interactive Teacher Deck.
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.