1. Warm Up Write each fraction in the simplest form. 1. 2. 3. 4. 4 8 1 2 4 8 1 2 6 9 2 3 12 48 1 4 5 25 1 5

2. Simplest Form (Fractions)
A fraction is in simplest form when the top and bottom cannot be any smaller (while still being whole numbers). Example: 2/4 can be simplified to 1/2 To simplify a fraction, divide the top and bottom by the highest number that can divide into both numbers exactly.

3. Rational Number
A rational number is a number that can be written as a fraction with integers as the numerator and denominator.  
This includes fractions, regular counting numbers, negative numbers, terminating decimals and repeating decimals.

4. In baseball, a player’s batting average compares the number of hits with the number of times the player has been at bat. The statistics on the next slide are for the 2006 Major League Baseball season.

5. Batting Average (thousandths)
Player
Hits
At Bats
Batting Average (thousandths)
Miguel Cabrera
Ichiro Suzuki
Hits
at Bats
195
576
195
576
195 ÷ 576 ≈ 0.339
224
695
224
695
224 ÷ 695 ≈ 0.322
To convert a fraction to a decimal, divide the numerator by the denominator.

6. Fractions as Decimals
Write each fraction as a decimal. Round to the nearest hundredth, if necessary. 1 4 9 5 5 3 A. B. C. 1 .8 1 .6 6 6
0.2 5
1.00 4 5
9.0 3
5.000
– 8
– 3
– 5 20 40 20
– 20
– 40
– 18 20
– 18 1 4 9 5
= 1.8 5 3
= 0.25 20
≈ 1.67
– 18 2

7. Check It Out: Example 1
Write each fraction as a decimal. Round to the nearest hundredth, if necessary. 3 4 6 5 7 3 A. B. C. 1 .2 2 .3 3 3
0.7 5
3.00 4 5
6.0 3
7.000
– 2 8
– 6
– 5 20 10 10
– 20
– 10
– 9 10
– 9 3 4 6 5
= 1.2 7 3
= 0.75 10
≈ 2.33
– 9 1

8. Write each fraction as a decimal. 4 5 A.
Fractions as Decimals
Write each fraction as a decimal.
4 5 A.
4 5
2 2
8 10
Multiply to get a power of ten in the denominator. x =
= 0.8
37 50 B.
37 50
2 2
74 100
Multiply to get a power of ten in the denominator. x =
= 0.74

9. Write each fraction as a decimal. 3 5 A.
Check It Out: Example 2
Write each fraction as a decimal.
3 5 A.
3 5
2 2
6 10
Multiply to get a power of ten in the denominator. x =
= 0.6
18 25 B.
18 25
4 4
72 100
Multiply to get a power of ten in the denominator. x =
= 0.72

10. The decimals 0.75 and 1.2 in Example 1 are terminating decimals because the decimals comes to an end.
The decimal 0.333…is a repeating decimal because the decimal repeats a pattern forever. You can also write a repeating decimal with a bar over the repeating part.
0.333… = 0.3
0.8333… = 0.83
… = 0.72

11. Write each decimal as a fraction in simplest form.
Decimals as Fractions
Write each decimal as a fraction in simplest form. A
B. 1.55 18
1,000
155
100
0.018 =
1.55 =
18 ÷ 2
1,000 ÷ 2
155 ÷ 5
100 ÷ 5 = = 9
500 31 20 11 20
or 1 = =
You read the decimal as “eighteen thousandths.”
Reading Math

12. Check It Out: Example 3
Write each decimal as a fraction in simplest form. A
B. 1.30 15
1,000
130
100
0.015 =
1.30 =
15 ÷ 5
1,000 ÷ 5
130 ÷ 10
100 ÷ 10 = = 3
200 3 10 = 13 10
or 1 =

13. Write each fraction as a decimal. 1. 3. 4.
Lesson Quiz
Write each fraction as a decimal. 1.
Write each decimal as a fraction in simplest form.
7. If your soccer team wins 21 out of 30 games, what is your team’s winning rate? 16 5 21 8
3.2 2.
2.625 7 10 11 20
0.7
0.55 21 50 69 8
5 8
or 8
0.70

14. Lesson Quiz for Student Response Systems
1. Which of the following represents the
fraction as a decimal?
A. 3.4
B. 3.5
C. 3.6
D. 3.7
18 5

15. Lesson Quiz for Student Response Systems
2. Which of the following represents the
fraction as a decimal?
A. 0.65
B. 0.75
C. 0.85
D. 0.95

16. Lesson Quiz for Student Response Systems
3. Which of the following represents the decimal 0.32 as a fraction in simplest form?
A C.
B D.
8 25
6 25
7 25
1 5

17. Lesson Quiz for Student Response Systems
4. Which of the following represents the decimal as a fraction in simplest form?
A. or 8 C. or 6
B. or 6 D. or 6
49 6
1 6
37 6
1 6
49 8
1 8
31 5
1 5

18. Lesson Quiz for Student Response Systems
5. If Rita scores 34 out of 50 in a class test, what is Rita’s scoring rate?
A. 0.65
B. 0.66
C. 0.67
D. 0.68