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Date
Time
LESSON
Factor Strings
19
䉬
A factor string is a name for a number written as a product of two or more factors.
In a factor string, 1 may not be used as a factor.
The length of a factor string is equal to the number of factors in the string. The
longest factor string for a number is made up of prime numbers. The longest factor
string for a number is called the prime factorization of that number.
Example:
Number
20
Factor Strings
Length
2 º 10
2
4º5
2
2º2º5
3
The order of the factors is not important.
For example, 2 ⴱ 10 and 10 ⴱ 2 are the same factor string.
The longest factor string for 20 is 2 ⴱ 2 ⴱ 5.
So the prime factorization of 20 is 2 ⴱ 2 ⴱ 5.
1.
Find all the factor strings for each number below.
a.
b.
Copyright © Wright Group/McGraw-Hill
Number
Factor Strings
Length
Number
Factor Strings
Length
Factor Strings
Length
16
12
c.
d.
Number
16
18
Factor Strings
Length
Number
28
16
For use on electronic devices only.
Created for Mr. Turner on 10/20/2010.
25
Date
Time
LESSON
Factor Strings
19
䉬
2.
continued
Write the prime factorization (the longest factor string) for each number.
a.
27 b.
40 c.
36 d.
42 e.
48 f.
60 g.
100 An exponent is a raised number that shows how many times the number
to its left is used as a factor.
Examples:
Copyright © Wright Group/McGraw-Hill
3.
4.
26
52 ∑ exponent
52 means 5 º 5, which is 25.
52 is read as “5 squared” or as “5 to the second power.”
103 ∑ exponent
103 means 10 º 10 º 10, which is 1,000.
103 is read as “10 cubed” or as “10 to the third power.”
24 ∑ exponent
24 means 2 º 2 º 2 º 2, which is 16.
24 is read as “2 to the fourth power.”
Rewrite each number written in exponential notation as a product of factors.
Then find the answer.
2 º 2 º 2
8
Examples: 23 36
2 º 2 º 9
22 º 9 a.
104 b.
32 º 5 c.
24 º 102 Rewrite each product using exponents.
53
Examples: 5 º 5 º 5 5º5º3º3
52 º 32
a.
3º3º3º3
b.
4º7º7
c.
2º5º5º7
d.
2º2º2º5º5
For use on electronic devices only.
Created for Mr. Turner on 10/20/2010.
Date
Time
LESSON
Math Boxes
19
1.
Circle the numbers that are divisible by 9.
360
252
819
426
651
2.
Round 385.27 to the nearest …
a.
hundred.
b.
whole number.
c.
tenth.
4 28–30
249
11
3.
Complete the table.
Fraction
4. a.
Decimal
Percent
3
ᎏᎏ
8
Write a 6-digit numeral with
7 in the thousands place,
5 in the hundredths place,
4 in the tenths place,
3 in the tens place,
and 9s in all other places.
60%
,
ᎏ2ᎏ
5
b.
.
Write this numeral in words.
0.55
Copyright © Wright Group/McGraw-Hill
ᎏ8ᎏ
100
80 90
5.
Complete.
a.
4 30 31
6. a.
How many marbles are in 7 bags
if each bag contains 8 marbles?
300 40 ⫽
b.
⫽ 80 200
c.
⫽ 900 600
d.
6,400 ⫽
e.
36,000 ⫽ 600 (unit)
b.
80
How many marbles are in 700 bags
if each bag contains 8 marbles?
(unit)
18
For use on electronic devices only.
Created for Mr. Turner on 10/20/2010.
18–20
27