Transcript Greatest Common Factor

• Elena, Joe, Owen, Samantha, and Tuck have
weighed their backpacks.
• Elena's backpack weighs the most.
• Owen’s backpack weighs 0.45 lb less than Joe's
backpack.
• Samantha's lunch weighs 1.5 lb. With that lunch
out of the backpack, the backpack weighs 16.55
lb.
• Tuck's backpack weighs more than Owen's.
• How much does each person's backpack
weigh?
Answer
• Elena: 19.8 lb
Joe: 19.35 lb
Owen: 18.9 lb
Samantha: 18.05 lb
Tuck: 19.5 lb
Lesson 5-8
LCM and Comparing and
Ordering Rational Numbers
LCM
• A multiple is a product of natural numbers.
Ex: 3 x 4 = 12, 12 is a multiple of 3 and 4.
• The least common multiple is the common
multiple that is less than any other
common multiple of two or more numbers.
• Three ways to find LCM: Listing multiples,
prime factorization, cake method.
Listing Multiples
• List multiples of each number from least to
greatest.
• Ex. 12 and 8
12: 12 24 36 48
8: 8 16
24
32
40
48
Listing Multiples
• List multiples of each number from least to
greatest.
• Ex. 12 and 8
12: 12 24 36 48
8: 8 16
24
32
The LCM is 24.
40
48
Prime Factorization
16
4
2
24
4
2
2
•2x2x2x2
•2x2x2x3
6
4
2
2
2
2
3
Prime Factorization
16
4
2
24
4
2
2
6
4
2
2
2
2
3
•2x2x2x2
•2x2x2x3
•Common: 2 x 2 x 2 x 2 x 3 = 48 LCM = 48
Cake Method
2
2
3
18
32
9
16
12
18
6
9
2
3
LCM = 288
2 x 2 x 3 x 3 = 36
LCM = 36
Your Turn
• Find the LCM of 10 and 15 by listing
multiples.
LCM = 30
• Find the LCM of 45 and 75 by using prime
factorization.
LCM = 225
• Find the LCM of 32 and 48 by using the
cake method.
LCM = 96
LCD
• A common denominator is a common
multiple of 2 denominators. The least
common denominator (LCD) is the LCM of
the denominators.
• Find the LCD of:
7
12
8
18
The LCD is 36
Compare the Fractions Using < or >
5
6
1
5
9
16
>
7
9
>
7
50
<
7
10
Order From Least to Greatest
0.6 48%
22%
1
5
0.3
2%
1
2
2
10
0.18
=
48%
1
2
=
2
10
22%
=
2%
0.18
0.6
0.3
1
5
Homework
• Complete Lesson 5-8 # 2-20 evens
• Don’t forget that you have a Chapter 5
Test on Friday!! Start Studying