Transcript Lesson 4.4 - Howell Township Public Schools

OBJ: To find the least common multiple of two
numbers.
Vocabulary
 Multiple- the product of the number and any nonzero
whole number.
 Common Multiple – a multiple that is shared by two or
more numbers.
 Least Common Multiple – the least of the common
multiples of two or more numbers.
 Least Common Denominator – the least common
multiple of the denominators. You can use the LCD to
compare and order fractions.
Finding the LCM
 Method 1
 List the multiples of
each number.
 Identify the least
number that is on both
lists.
 Example – Find the
LCM of 16 and 24.
 Method 2
 Find the common
factors of the numbers.
 Multiply all of the
factors, using each
common factor only
once.
 Example – Find the
LCM of 16 and 24.
Find the LCM of
1.
2.
3.
4.
5.
6.
7.
20 and 25
6, 8, and 20
15, 30, 50
15x2, 27x
6m2, 10m3
14ab and 21bc
4g3h2 and 15g2h4
Least Common Denominator
 Write the fractions and simplify.
 Find the LCD of the fractions.
 Write the equivalent fractions using the LCD.
 Compare the numerators.
 Example – Find the LCD and compare the fractions.
 5/6, 7/9
 5/8, 13/20
 7/12, 11/15
 5/16, 3/10
Examples
 One brand of hot dogs is sold in packages of 6. One
brand of hot dog buns is sold in packages of 8. What
is the least number of hot dogs Kimberly can buy and
be able to buy an equal number of hot dog buns?
 Last year a poll of 1200 students found that 300 spoke a
first language other than English. This year a poll of
10,000 students found that 4000 students spoke a first
language other than English. In which year was the
fraction of non-English first language speakers
greater?
 How do you find the LCM of two or more
numbers?
 What is the least common multiple of three
numbers that are relatively prime?