Find the LCM of 6 and 2 by listing multiples.
6
The first positive multiple shared by 6 and 2 is 6.
Day 012Least Common Multiples
Standards 6.NS.B.4b
LEARNING TARGET
I can find the least common multiple of two numbers no greater than 12.
01 · LEARN
Build the idea
List positive multiples of both numbers. The smallest shared multiple is the LCM. Repeating events that begin together next occur together after this many time units.
Two lights flash together now, then every 9 and 12 seconds. When do they next flash together? Explain.
36 seconds
The first positive multiple shared by 9 and 12 is 36.
02 · PRACTICE
Your turn
Work in order. Start with the foundations, then build toward explanation and application.
Find the LCM of 4 and 3 by listing multiples.
Find the LCM of 4 and 6 by listing multiples.
Find the LCM of 5 and 4 by listing multiples.
Find the LCM of 9 and 11 by listing multiples.
Find the LCM of 6 and 3 by listing multiples.
Find the LCM of 10 and 8 by listing multiples.
Two lights flash together now, then every 2 and 3 seconds. When do they next flash together? Explain.
Two lights flash together now, then every 11 and 12 seconds. When do they next flash together? Explain.
Two lights flash together now, then every 3 and 5 seconds. When do they next flash together? Explain.
Two lights flash together now, then every 4 and 10 seconds. When do they next flash together? Explain.
03 · CHECK
Answers and reasoning
Reveal the teacher answer key
- 12
The first positive multiple shared by 4 and 3 is 12.
- 12
The first positive multiple shared by 4 and 6 is 12.
- 20
The first positive multiple shared by 5 and 4 is 20.
- 99
The first positive multiple shared by 9 and 11 is 99.
- 6
The first positive multiple shared by 6 and 3 is 6.
- 40
The first positive multiple shared by 10 and 8 is 40.
- 6 seconds
The first positive multiple shared by 2 and 3 is 6.
- 132 seconds
The first positive multiple shared by 11 and 12 is 132.
- 15 seconds
The first positive multiple shared by 3 and 5 is 15.
- 20 seconds
The first positive multiple shared by 4 and 10 is 20.