6th Grade · The Number System
Least Common Denominator
6.NS.B.4
Definition
The smallest common multiple of two or more denominators, used to add or subtract fractions.
Teach it
Where it is taught, with guided notes, practice, homework, an exit ticket and an interactive Teacher Deck.
Examples
- For denominators 4 and 6, the LCD is 12.
- Use the LCD to rewrite fractions before adding or subtracting.
Key rule
The least common denominator is the LCM of the denominators.
Memory hook
Smallest shared denominator, ready to add or subtract.