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When estimating fractions you can use
2 different strategies.
Use Compatible
Numbers…
…when multiplying a
whole number and a
fraction.
65
x 37
…when multiplying a
mixed number and a
fraction.
3
16
3
5
x 4
When estimating fractions you can use
2 different strategies.
Use Compatible
Numbers…
…when multiplying a
whole number and a
fraction.
65 x
3
7
…when multiplying a
mixed number and a
fraction.
3
16
3
5
x 4
Use Rounding…
…when multiplying two
mixed numbers.
17
4
7
x
2
…when multiplying a
mixed number and a
whole number.
5 2
x
9
10
1
2
Type of Problem
Whole Number
X Fraction
Example
5
6
x
41
Best
Strategy
Compatible
Numbers
When
estimating a
product of a
fraction and a
whole number,
use
compatible
numbers.
42 ÷ 6 = 7
7 x 5 = 35
Step 1:
5 x
6
≈
41 35
5 x
6
42
Step 2:
Step 3:
Step 4:
Find the closest Rewrite the problem Divide the whole Multiply the
quotient by the
basic math fact with the compatible number by the
denominator.
numerator.
numbers.
to 6 and 41.
Type of Problem
Example
Mixed Number
X Fraction
41
x 13 29
5
6
Whole Number
X Fraction
5
7
x
Best
Strategy
Compatible
Numbers
Compatible
Numbers
When
estimating a
product of a
fraction and a
mixed number,
use compatible
numbers.
14 ÷ 7 = 2
2 x 5 = 10
Step 1:
5
7
x
5
7
x
Step 2:
13
2
9
14
Step 3:
≈ 10
Step 4:
Find the closest Rewrite the problem Divide the whole Multiply the
quotient by the
basic math fact with the compatible number by the
denominator.
numerator.
to 7 and 13 29 . numbers.
Type of Problem
Example
41
Mixed Number
2
5 x
13 9
X Fraction
7
Mixed Number
2 x
1
39
X Mixed Number 10 3
Whole Number
X Fraction
5
6
x
Best
Strategy
Compatible
Numbers
Compatible
Numbers
Round
Think:
2
1
3
2
Add 1 More!
1
1
9
2
Just Ignore!
V
V
Think:
10 3
x
=
11 3 33
When
estimating
a product
of mixed
numbers,
use
rounding.
2x
3
1
9
Type of Problem
Example
41
Mixed Number
2
5 x
13 9
X Fraction
7
Mixed Number
2 x
1
39
X Mixed Number 10 3
Whole Number
3 x
7
X Mixed Number 4 4
Whole Number
X Fraction
5
6
x
Best
Strategy
Compatible
Numbers
Compatible
Numbers
Round
Round
Think:
V
3
1
4
2
Add 1 More!
When
estimating
a product
of a mixed
number and
a whole
number, use
rounding.
4 7
x
=
5 7 35
3x
4
Type of Problem
Example
41
Mixed Number
2
5 x
13 9
X Fraction
7
Mixed Number
2 x
1
39
X Mixed Number 10 3
Whole Number
3 x
7
X Mixed Number 4 4
Whole Number
X Fraction
5
6
x
Best
Strategy
Compatible
Numbers
Compatible
Numbers
Round
Round
When
estimating a
product of a
fraction and a
whole number,
use
compatible
numbers.
30 ÷ 5 = 6
6 x 2 = 12
Step 1:
32
2
x ≈
5
30
2
x
5
Step 2:
Step 3:
12
Step 4:
Find the closest Rewrite the problem Divide the whole Multiply the
quotient by the
basic math fact with the compatible number by the
denominator.
numerator.
numbers.
to 5 and 32.
Think:
3
1
8
2
Just Ignore!
7
1
9
2
Add 1 More!
When
estimating
a product
of mixed
numbers,
use
rounding.
V
V
Think:
8 4
x
=
8 5 40
3x
8
7
9
When
estimating a
product of a
fraction and a
whole number,
use
compatible
numbers.
42 ÷ 6 = 7
7 x 5 = 35
Step 1:
5 x
6
≈
41 35
5 x
6
42
Step 2:
Step 3:
Step 4:
Find the closest Rewrite the problem Divide the whole Multiply the
quotient by the
basic math fact with the compatible number by the
denominator.
numerator.
numbers.
to 6 and 41.
Compatible numbers allow you to estimate quotients by
changing the dividend and the divisor into a basic math
fact.
Division
Problem
Closest Basic
Math Fact
Estimation
98 ÷ 9
99 ÷ 9 =
11
55 ÷ 8
56 ÷ 8 =
7
29 ÷ 7
28 ÷ 7 =
4
40 ÷ 6
42 ÷ 6 =
7
11 ÷ 3
12 ÷ 3 =
4
Find you’re your number,
5
7
4
2
9
3
Think:
Think:
4
2
1
9
3
2
Just1Ignore!
Add
More!
V
1
Less
Four than
or less
2 , just ignore,
1
Five
2 or more, add one more.
V
Look right next door
8
5
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