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5 Minute Check
Estimate. Complete in your notebook.
1.
1
5
x 26
2.
5
7
x
3.
1
3
4
1
9
x2
3
4
5 Minute Check
Estimate. Complete in your notebook.
1.
1
5
x 26
5 Minute Check
Estimate. Complete in your notebook.
1.
1
5
x 26 ≈ 5
1
5
x 25 =
1
5
25
1
x =
25
5
=5
5 Minute Check
Estimate. Complete in your notebook.
2.
5
7
x
1
9
5 Minute Check
Estimate. Complete in your notebook.
2.
5
7
1
9
x
1
2
x0=0
≈0
5 Minute Check
Estimate. Complete in your notebook.
3.
4
1
3
x
2
3
4
5 Minute Check
Estimate. Complete in your notebook.
3.
4
1
3
x
3
4
2 ≈ 12
4 x 3 = 12
Flashcards
Tuesday, Oct 22
Lesson 4.2
Multiply Fractions and Whole Numbers
Multiply Fractions and Whole Numbers
Objective: To understand how to multiply
fractions and whole numbers.
Multiply Fractions and Whole Numbers
At the end of this lesson you should be able
to answer the following question.
How is the process used to multiply a fraction
and whole number similar to the process used
to multiply two whole numbers?
Multiply Fractions and Whole Numbers
To multiply fractions, multiply the numerators
and multiply the denominators, then simplify if
needed.
Example x
=
3
2
6
4
5
20
x
=
x
=
=
3
10
Multiply Fractions and Whole Numbers
To multiply a fraction and whole number,
convert the whole number to a fraction, then
multiply as before.
Example 2
5
x 14
2
5
x
x
x
14
1
=
28
5
3
5
= =5
=
Multiply Fractions and Whole Numbers
Multiply.
2
5
2x =
Estimate?
Multiply Fractions and Whole Numbers
Multiply.
2
5
2x =
Estimate?
2
1
x
2
4
4
4
= =1
Actual Product?
Multiply Fractions and Whole Numbers
Multiply.
2
5
2x =
Actual Product?
2
1
x
2
5
=
4
5
Is this a reasonable answer?
Multiply Fractions and Whole Numbers
Multiply.
2
5
2x =
Actual Product?
2
1
x
2
5
=
4
5
4
Is this a reasonable answer? 5
≈1
Multiply Fractions and Whole Numbers
Multiply.
2
3
6x =
(Do this on your own)
Multiply Fractions and Whole Numbers
Multiply.
2
3
6x =
Estimate?
Multiply Fractions and Whole Numbers
Multiply.
2
3
6x =
Estimate?
Since 3 and 6 are in the same multiples list we
really do not need an estimate.
Actual Product?
Multiply Fractions and Whole Numbers
Multiply.
2
3
6x =
Actual Product?
6
1
x
2
3
12
3
= =4
Multiply Fractions and Whole Numbers
When multiplying a fraction by a whole
number, the order of the factors does not
change the product. This is true for any
numbers and is an example of the
Commutative Property.
Example
2x5=5x2
Multiply Fractions and Whole Numbers
Multiply.
3
5
4x =
Estimate?
Multiply Fractions and Whole Numbers
Multiply.
3
5
4x =
Estimate?
4
1
x
3
4
=
Actual Product?
12
4
=3
Multiply Fractions and Whole Numbers
Multiply.
3
5
4x =
Actual Product?
4
1
x
3
5
12
5
= =2
2
5
Is this a reasonable answer?
Multiply Fractions and Whole Numbers
Multiply.
3
5
4x =
Actual Product?
4
1
x
3
5
12
5
= =2
2
5
Is this a reasonable answer?
2
5
2 ≈3
Multiply Fractions and Whole Numbers
Multiply.
1
4
x5=
Estimate?
Multiply Fractions and Whole Numbers
Multiply.
1
4
x5=
Estimate?
1
4
4
1
4
4
x = =1
Actual Product?
Multiply Fractions and Whole Numbers
Multiply.
1
4
x5=
Actual Product?
1
4
x
5
1
5
4
1
4
= =1
Is this a reasonable answer?
Multiply Fractions and Whole Numbers
Multiply.
1
4
x5=
Actual Product?
1
4
x
5
1
5
4
1
4
= =1
Is this a reasonable answer?
1
4
1 ≈1
Multiply Fractions and Whole Numbers
4
A sloth spends 5 of it’s life asleep. If a
sloth lives to be 28 years old, how many
years does it spend asleep?
(Do this on your own)
Multiply Fractions and Whole Numbers
4
A sloth spends 5 of it’s life asleep. If a
sloth lives to be 28 years old, how many
years does it spend asleep?
Estimate?
Multiply Fractions and Whole Numbers
4
A sloth spends 5 of it’s life asleep. If a
sloth lives to be 28 years old, how many
years does it spend asleep?
Estimate?
4
5
30
1
x =
120
5
Actual Product?
= 24
Multiply Fractions and Whole Numbers
4
A sloth spends 5 of it’s life asleep. If a
sloth lives to be 28 years old, how many
years does it spend asleep?
Actual Product?
4
5
28
1
x =
112
5
= 22
Is this a reasonable answer?
2
5
Multiply Fractions and Whole Numbers
4
A sloth spends 5 of it’s life asleep. If a
sloth lives to be 28 years old, how many
years does it spend asleep?
Actual Product?
4
5
28
1
x =
112
5
= 22
Is this a reasonable answer?
2
5
2
5
22 ≈ 24
Multiply Fractions and Whole Numbers
One evening, 2/3 of Mrs. Thorne’s students watched a
reality TV show. Of Mrs. Lombardo’s students, 4/5
watched the same reality show. Which teacher had
more students watch the show?
(Do this on your own)
Multiply Fractions and Whole Numbers
One evening, 2/3 of Mrs. Thorne’s students watched a
reality TV show. Of Mrs. Lombardo’s students, 4/5
watched the same reality show. Which teacher had
more students watch the show?
Mrs. T
2
3
72
3
=24
120
5
= 24
x =
Mrs. L
4
5
36
1
30
1
x =
Multiply Fractions and Whole Numbers
Natalie multiplied 2/3 by 123 and got
156. Is this a reasonable answer?
Multiply Fractions and Whole Numbers
Natalie multiplied 2/3 by 123 and got
156. Is this a reasonable answer?
No, because if you multiply a whole
number by a fraction the answer will
always be less than the whole number.
Multiply Fractions and Whole Numbers
How is the process used to multiply a
fraction and whole number similar to the
process used to multiply two whole
numbers?
Multiply Fractions and Whole Numbers
Agenda Notes
Homework –
Homework Practice 4-2
Show all work
Due Wednesday, Oct 23
Mid Chapter 4 Quiz –Monday, Oct 28