Fraction, Decimal, Percent
TEKS Student Expectation:The student is expected to convert between fractions, decimals, whole numbers and percents mentally, on paper, or with a calculator. (7.1B)
Materials / Vocabulary / Warm-up
For teacher
· Student fraction sheet
· Teacher transparency / Per student
· Fraction sheet
· Transparency of Grid A and Grid B
· calculator / · Decimal
· Fraction
· Equivalent fraction / Change Maker
Cost: $1.83
Coins presented:
$, Q, Q, Q, D
Activity: Today we will use a decimal transparency and a calculator to find equivalent decimals, fractions and percents.
1. The teacher says:
· How are decimals and fractions alike? (They can both be used to name parts of a whole.)
· How do percents relate to fractions and decimals? (percents also can be used to name parts of a whole, where the whole is equivalent to 100)
2. Remind the students that a fraction is a ratio of the part to the whole and in a model the part will be shaded.
3. The teacher says:
· What does each section in grid A represent? () How do you know? (the square is divided into 10 equal size pieces)
· How can you write that as a decimal? (0.1) Explain your reasoning.
· What does one small square in grid B represent? ( ) How do you know? (the square is divided into 100 equal size pieces)
· How can you write that as a decimal? (0.01) Explain your reasoning.
· How many hundredths from grid B would be equivalent to one section in grid A? (10)
· Give me a fraction with a denominator of 100 equivalent to . ()
· How does this fraction relate to a percent? (it is 10% because the fraction is ten one-hundredths or ten out of one hundred)
· Give me a decimal statement that says = . (0.1 = 0.10)
· How does this decimal relate to a percent? (it is also 10% because it’s value is ten one-hundredths)
4. Model the next section for the students using the transparency models of the fractions and the decimal overlay sheet. The teacher says:
· What fractional part of figure 1 is shaded? Record your fraction in the space provided.
· Lay the transparency grid A on top of the figure 1.
· How many sections are shaded on the transparency? (5)
· What fraction could I write to represent this amount? () Explain your reasoning. (each section is one tenth and there are five of them shaded)
· Record your fraction in the space provided.
· Lay the transparency grid B on top of figure 1.
· How many sections are shaded on the transparency? (50)
· What fraction could I write to represent this amount? () Explain your reasoning. (each section represents one hundredth and there are 50 of them shaded)
· Record your fraction in the space provided.
· How are the fractions , and related? (they are equivalent fractions) Why do you say that? (they all have the same amount of shaded area)
· What are the decimals I could write for and ? (0.5 and 0.50)
· Record your decimals in the spaces provided.
· Percents are used to name parts of a whole, where the whole is equivalent to 100. What percent of figure 1 is shaded? (50%) Why do you say that? (50 of the 100 parts are shaded)
· Record your percent in the space provided.
· What conclusion can be drawn when we compare the values , , , 0.5, 0.50 and 50%? (All of the values represent the shaded area. All of the values represent the same amount.)
· Complete the remainder of the lines below the models. You can use the transparencies to help you.
5. Give students time to complete the number sentences and then have them share their answers and strategies with the class. Be sure that you discuss the fact that did not fit nicely into the squares and you had to estimate of a square.
6. The teacher says:
· Another way of looking at the fraction is 1 divided by 2. Use your calculator to find 1 divided by 2. What answer did you get? (0.5) Compare your calculator answer to the decimal value in figure 1.
· Use your calculator to find 4 divided by 5. What answer did you get? (0.8) Compare your calculator answer to the decimal value in figure 2.
· Use your calculator to divide the numerators by the denominators for the rest of the fractions on your model sheet. (give students time to finish)
· What did you notice about the division you did on your calculator and the decimals you found by using equivalent fractions? (They are the same)
· Change the following fractions to decimals by finding equivalent fractions using your calculator.
1
Journal Prompt: Give a situation where you might want to write a part of something as a decimal and a situation where you might want to use a fraction? Tell why you think you should use the fraction or the decimal for your situations.
Decimal transparency (one set of grids per Student)
Teacher transparency
Student fraction sheet
Number, Operation, and Quantitative Reasoning 2006-2007 Page 7 of 7