Transcript Dividing Rational Numbers

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Objective
Divide fractions
Vocabulary
Multiplicative inverses
Two numbers whose product is 1
Vocabulary
Reciprocal
Another name for multiplicative inverse
Vocabulary
Inverse Property of Multiplication
A product of a rational number and its
multiplicative inverse is 1
Review
Vocabulary
Additive inverse
The sum of any number and its additive inverse
is zero
A + (-a) = 0
4 + (-4) = 0
Example 1
Divide Fractions
Example 2
Divide by a Whole Number
Example 3
Divide by Negative Fractions
Example 4
Divide Mixed Numbers
Find
Write in simplest form.
Write problem
Use calculator
Put first fraction in the calculator
3
a b/c
10

2
a b/c
5
=
Push the division symbol ()
Put second fraction in the calculator
Push the equal sign (=)
Answer:
1/4
Find
Write in simplest form.
Answer:
1/4
Find
Write in simplest form.
Write problem
Use calculator
Put first fraction in the calculator
6
a b/c
7

12
=
Push the division symbol ()
Put the whole number in the calculator
Push the equal sign (=)
Answer:
2/4
Find
Write in simplest form.
Answer:
2/4
Find
Write in simplest form.
Write problem
Use calculator
Put first fraction in the calculator
2
a b/c
7

8
a b/c
9
+/-
=
Push the division symbol ()
Put second fraction in the calculator
Put the negative sign in calculator (+/-)
Push the equal sign (=)
Answer:
3/4
Find
Write in simplest form.
Answer:
3/4
Find
Write in simplest form.
Write problem
Put first fraction in the calculator
Push the division symbol ()
3
a b/c
1
a b/c
4

2
a b/c
1
a b/c
8
+/-
=
Put second fraction in the calculator
Put the negative sign in calculator (+/-)
Push the equal sign (=)
Answer:
4/4
Find
Write in simplest form.
Answer:
4/4
Assignment
Lesson 2:4
Dividing Rational
Numbers
20 - 37 All
Write the multiplicative inverse of
Write problem
Convert mixed number to improper fraction
Put the whole number in the calculator
which is -2
2 +/-

7
+
4
Multiply by the denominator which is 7
Add numerator which is 4
Write the multiplicative inverse of
Write
Answer: Since
of
as an improper fraction.
the multiplicative inverse
Write the multiplicative inverse of
Answer:
MOVIES One summer day, a cinema shows a hit
action movie repeatedly for
hours. It takes
about 150 minutes to run the movie and prepare for
the next showing. How many times does the
cinema show the movie that day?
Must have same dimensional analysis to divide
Change hours to minutes
12 ½ times 60 minutes
12 ½ times 60 minutes
750 minutes in 12 ½ hours
Each showing is 150 minutes so now divide
Answer: The cinema shows the movie 5 times that day.
*
ZOOS A zoo has a reptile show that runs repeatedly
for
hours. It takes about 105 minutes to conduct
the show and prepare for the next one. How many
times does the zoo run the reptile show each day?
Answer: 6 times