6th Grade Math Textbook, Fundamentals

Lesson 5-9 for exercise sets. &KDSWHU 

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Multiply: 3• 2

Estimate first:  3  4 2  2 4 • 2  8

Then multiply:

3• 2 • Rename each mixed number.



 Divide to rename as a mixed number.

 8  8 Express the fraction part in simplest form.

Multiply the numerators.

Multiply the denominators.

1

10

18 • 9

5 • 4

9

4

1

4

3

5

1

4

3

5

2

20

 162

20

 18

5

1

4

3

(^25)
Multiply: 4 • 9
Estimate first. Then multiply.
4  5 5 • 9 45
4 • 9  •
 Divide to rename.
 44
Rename the factors, then
multiply.
1
10
441
10
9
1
49
10
9
10
9
10
9
(^310) Multiply: 2 •
Estimate first. Then multiply.
2  2  1 2 • 1  2
2•  • Rename 2 , then multiply.
 Divide to rename.
 2241
49
24
1
3
7
8
7
3
7
8
1
3
7
8
1
3
7
8
1
(^43)
Think
44101 is close to 45.
Think
2241 is close to 2.

You can evaluate algebraic expressions involving multiplication of fractions.

Evaluate a• b, when a and b.

• ()

 Multiply.



Substitute the

known values.

 2

3

 6

7

 2 ( 2 )

7 • 1

4

7

 62

7 3

2

1



()

 2

3

 6

7 Evaluate a• b, when a3 and b.

3• () • ()

 Multiply.

 Divide to rename.

 2

Substitute the

known values.

 2

3

4

15

 34

15

17

5

2

5

2

5

 2

3

17 ( 2 )

5 • 3

 2

3

Estimate. Then multiply. Express the product in simplest form.

1.4• 4 2. (^3) ( (^1) ) 3. (^1) ( (^1) ) 4.2• 1 5.3(7)
Evaluate.
6.a• b, when a , b 7.a• b, when a 4, b
8.Discuss and Write Explain why estimation is or is not helpful when multiplying
various kinds of fractional numbers. Support your answer with examples.
 2
3
7
9
3
4
 3
8
3
4
1
2
1
2
7
8
1
6
2
3
1
2
1
2
3
5
Think
 8101 is close to 8.

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