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Lesson 3
Equivalent Rational Numbers
Rational Number
• A rational number can be expressed as a
fraction or mixed number, a decimal or a
percent. We will cover rational numbers
more in a few lessons.
Example 1
• How would 14/16 be expressed as a
decimal?
• First, how do you change a fraction to a
decimal?
– Divide the numerator by the denominator.
(Flower story)
• 14 ÷ 16= .0875. So, 14/16 = .0875
Example 2
• If 1 out of 3 students in class plays a musical
instrument, what percent of the students in her
class play a musical instrument?
• First, change the fraction 1/3 to a decimal.
• Then, take the decimal 0.3333… and move the
decimal point 2 places to the right to make it a
percent. (It is the same as multiplying by 100)
• 33.3% of the students play a musical instrument.
Example 3
• The population growth of Melvin’s city from
1950 to 2000 was 325%. How could 325%
be expressed as a mixed number?
• All percents are out of 100, so we would
rewrite 325% to be 325/100.
• That is an improper fraction. Now, we
change the improper fraction to a mixed
number.
• 325/100 = 3 25/100 = 3 1/4
Example 4
• Jill’s savings bond earned 0.5% interest.
How would 0.5% be expressed as a
decimal?
• To change a percent to a decimal, move
the decimal point to the left 2 places (it is
the same as dividing by 100).
• So, 0.5= 0.005
Lets Practice
• Forty five percent of the students in town
take the bus to school. What fraction of
students take the bus to school?
• In a recent election, 2/5 of the registered
voters actually voted. What decimal is
equivalent to 2/5?
• What percent is equivalent to 0.001?
• Luther received a 4.5% raise in his salary.
What decimal is equivalent to 4.5%?
More Practice
• A survey found that 2/3 of the 8th grade students
plan to take Spanish in high school. What
percent of the 8th grade place on taking Spanish
in High School?
• What decimal is equivalent to 0.08%?
• A technology company’s profits are up 225%
from last year. Which decimal is equivalent to
225%?
• Mr. Simmons enlarged a photo by 150%. What
mixed number is equivalent to 150%?
Explain yourself
• Frank read that argon makes up 0.9% of
the Earth’s atmosphere.
– Express 0.9% as a decimal.
– Explain how you found your answer and show
your work.
– Hand this open ended response in when you
are finished.