Post on 06-Feb-2016
description
Does the inverse relationship between multiplication and division stay the same when multiplying and dividing
fractions?
In this lesson you will learn how to check your answers when dividing fractions by thinking about the inverse
relationship between multiplication and division.
Let’s ReviewLet’s Review
4 x 6 = 246 x 4 = 2424 _ 6 = 424 _ 4 = 6
Fact Families are a collection of related facts.
4 6
24
Let’s ReviewLet’s Review 35 _ 7 = 5How can I
check to see if my answer is
correct?
So…35 divided into 7
equal groups results in 5 per group.
I know that seven groups of five is 35…
Let’s ReviewA Common Mistake
A common mistake is to forget that the inverse relationship of multiplication and
division remains the same, no matter what kind of numbers you are working with.
2 _ = 3
2 _ 3 =
3 x = 2
x 3 = 2
Let’s ReviewCore Lesson
_ = ?
1 whole
1 whole
14
14
14
14
18
18
18
18
1818
18
18
14
14
14
3
18
18
281
18
18
28
18
18
282 3
Does this answer
make sense?
Let’s ReviewCore Lesson
1 whole18
18
28
18
18
28
18
18
28
14
14
14
14
14
14
14
34
x =
This answer makes sense!
_ =
Let’s ReviewCore Lesson
_ = ?
12
12
18
18
18
18
1818
18
18
1818181818
One set of …
45
11 2 3 4 This answer makes sense because it is less than 1.
My answer should be less
than 1.
Let’s ReviewCore Lesson
x =
=
_ =
x =
In this lesson you have learned how to check your answers when dividing fractions by thinking about the inverse
relationship between multiplication and division.
Let’s ReviewGuided Practice
_ =
Let’s ReviewGuided Practice
_ =
Let’s ReviewExtension Activities
Charlie solved these three division problems. Please check his work by using related multiplication facts. Are his answers correct?
_ =
_ =
2 _ =
Let’s ReviewExtension Activities
Use a deck of cards (1 – 10 only) to create division problems. If you happen to create an improper fraction (numerator greater than denominator), you may switch the order of the cards or change it to a mixed number if you wish.
Now SOLVE. (If necessary, use fraction bars to build and solve the problems.)
Place four cards as shown.
_CARD CARD
CARD CARD
Be sure to check your answers by using multiplication!
Let’s ReviewQuick Quiz
Solve each problem. Use multiplication to check your answers.
_ = ?
1 _ = ?