Name
Least Common Multiple
Models and Examples
You can multiply a number by other numbers to find a multiple.
Some multiples of 8 are:
8
16
24
32
40
48
Some multiples of 12 are:
(8 1)
(8 2)
(8 3)
(8 4)
(8 5)
(8 4)
12 (12 1)
24 (12 2)
36 (12 3)
48 (12 4)
60 (12 5)
Notice: 24 and 48 are in both sets. They are common multiples of 8 and 12.
The smallest number that both 8 and 12 divide evenly is 24.
So, 24 is the least common multiple of 8 and 12.
The least common multiple of two numbers is the
smallest product that both numbers divide evenly.
Least common multiple
is abbreviated LCM.
More Examples
What is the least common multiple of 3 and 15?
Multiples of 3: 3, 6, 9, 12, 15, 18
Multiples of 3 skip count by 3s!
Multiples of 15: 15, 30, 45
Multiples of 15 skip count by 15.
15 is the first multiple common to both 3 and 15.
So 15 is the least common multiple of 3 and 15.
Guided Practice
Tell whether 20 is a common multiple for each pair of numbers.
Circle yes or no.
4 and 10
5 and 10
20 and 40
yes
yes
yes
no
© CSL Associates, Inc. (877) 790-7915
no
ARITHMETIC TO ALGEBRA
no
IL Workbook R
23
Name
Least Common Multiple
Practice
Tell whether 40 is a common multiple for each pair of numbers.
Circle yes or no.
4 and 10
8 and 20
20 and 40
yes
yes
yes
no
no
no
Tell whether 100 is a common multiple for each pair of numbers.
Circle yes or no.
10 and 20
25 and 50
50 and 60
yes
yes
yes
no
no
no
Find the least common multiple for each pair of numbers.
9 and 12
5 and 18
6 and 18
16 and 20
36 and 48
40 and 80
Find the least common multiple for each set of numbers.
24
9, 18, 36
3, 15, 25
2, 3, 10
8, 16, 24
IL Workbook R
ARITHMETIC TO ALGEBRA
© CSL Associates, Inc. (877) 790-7915