Transcript 5.NF.5 - IL K-5 Math Teach & Talk

5.NF.5
Interpret multiplication as scaling
• 5.NF.5a: Compare Products: Comparing the size of a
product to the size of one factor on the basis of the size of
the other factor, without performing the indicated
multiplication.
• 5.NF.5b: Explain the Results of Multiplying by a
Fraction: Explaining why multiplying a given number by
a fraction greater than 1 results in a product greater than
the given number (recognizing multiplication by whole
numbers greater than 1 as a familiar case); explaining why
multiplying a given number by a fraction less than 1
results in a product smaller than the given number; and
relating the principle of fraction equivalence a/b = (n×a) /
(n×b) to the effect of multiplying a/b by 1.
Without performing multiplication determine
whether the product is <, >, or = to 6.
Explain your reasoning.
2
x 6
4
3
x 6
6
4
x
6
2
3
2 x6
4
By comparing the sizes of the products for each circle, what
pattern do you observe when you multiply a fraction by
? 2
2
⅛
¼
⅛
¼
1 x 2 = 2
4
2
2
2 x 2 = 4
8
4
2
⅛
⅛
4
8
5th
5.NF.5
Mathematical Practice(s): 2
Without performing the indicated multiplication, use < ,
>, or = to make each equation true by comparing the size
of the product to the size of one factor on the basis of the
size of the other factor.
461 x 3
3
461 x 7
3
461 x 3
3
461 x 2
3
5.NF.5
Mathematical Practice(s): 2
Without performing the indicated multiplication,
use < , >, or = to make each equation true.
643 x 2
2
643 x 7
7
643 x 4
8
461 x 1
2
5.NF.5
Mathematical Practice(s): 2
Are the statements below True or False
about the product of 372 and ¼ ?
The product is less than 272 x ¼
The product is greater than 272 x ¼
The product is less than 372
The product is greater than 372
5.NF.5
Mathematical Practice(s): 2
Are the statements below True or False
6
about the product of 485 and ?
3
2
The product is less than 485 x 3
8
The product is greater than 485 x
3
The product is less than 485
The product is greater than 485
Mathematical Practice(s): 2
5.NF.5
Write Yes or No to indicate whether each fraction
can make the equation a true inequality
2
×
3
10
4
4
4
4
10
2
>
3
Mathematical Practice(s): 2
5.NF.5
Write Yes or No to indicate whether each fraction
can make the equation a true inequality
5
×
6
10
14
8
8
14
10
5
>
6
Mathematical Practice(s): 2
5.NF.5
Move each equation to the correct box
3 x 1
5
2
3 x 8
5
3
Less Than ⅗
3 x 1
5 10
3 x 4
5
5
Equal to ⅗
3 x 5
5
5
3
5
Greater Than ⅗
X
5