Math 6 NOTES (2.1a)
Name____________________________
Least Common Multiple (LCM)
TERM
Multiple
DEFINITION
EXAMPLE
Least Common
Multiple
Find the LCM…
Method #1 – List the multiples of each number.
Multiples of 6:
Multiples of 10:
Write the multiples of each number.
Start with the greater number.
Stop when you find a common
multiple!
What is the least common multiple?
TRY IT!
1)
Find the LCM of 3 and 12. (Remember to start with the greater number).
3:
12:
2)
Find the LCM of 4 and 5.
4:
5:
Math 6 NOTES (2.1b)
Name____________________________
Equivalent Fractions
Equivalent fractions are fractions that name the amount in different ways.
Example:
1 3

2 6
Drawing:
Steps to finding equivalent fractions
Ex:
1
3
1.
1
3
2.
1
2 2
x
=
3
2 6
3.
2
is an equivalent fraction
6
1. Rewrite your original fraction.
2. Multiply it by a whole number in the
form of a fraction with the same number
in the numerator and denominator.
3. The product is an equivalent fraction.
Directions: Find the missing numbers in the equivalent fractions
Example
20
2 40
x 
2
2 4
Math 6 NOTES (2.1c)
Name____________________________
Least Common Denominators (LCD)
 We use least common multiples and equivalent fractions to find the least common
denominator of two or fractions.
 Least common denominators are necessary when adding, subtracting, comparing and
ordering fractions.
 To create fractions with common denominators:
1. Identify the least common multiple of the denominators of the fractions you are
working with.
2. Create equivalent fractions with that least common multiple as the denominator.
Examples – Find the LCD of each set of fractions and re-write as equivalent fractions.
1)
4)
1
3
2
3
and
and
3
9
5
8
2)
5)
3
4
1
9
and
and
5
6
2
5
3)
6)
3
5
9
10
and
and
1
2
1
3
Math 6 Homework (2.1)
Find the LCD of each set of fractions and re-write as equivalent fractions.
1)
4)
7)
10)
2
3
1
2
3
4
2
3
and
and
and
and
4
9
7
8
5
9
8
9
2)
5)
8)
11)
4
5
1
8
5
6
2
9
6
and
and
and
and
7
1
4
7
8
1
4
3)
6)
9)
12)
4
5
9
10
5
7
7
9
and
and
and
and
1
3
4
5
2
3
5
7