Lesson 57: Defining Percentage, Rate or Percent and Base

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Mental Computation

Drill on Renaming Fractions to Decimals to Ratio and Vice-Versa

1/2

2/5

Review:� Matching Game

Mechanics:� 1. Teacher post the 2 charts on the board.

2. Divide the class into 3 group. Give each group a well shuffled set of a number cards.These cards are then distributed to the group members with each receiving one card.

3. When the signal is given by the teacher, a pupil from each group simultaneously goes to the board and places the number card in the correct slot.

4. The pupils will go to their group and tap the next player. Continue this until the chart has been completed.

5. The group that finishes first, with the most number of correct answers win.

Motivation:� Showing a paper clips. Where do we used these paper clips?�

Problem Opener:

Rafaela has 10 paper clips. She gives 2 paper clips to her seatmate and keeps the rest for the future use. Is it right for her to say that she keeps 80% of the paper clips?

Questions to answer:

1. Who has 10 paper clips?

2. To whom does she give 2 paper clips?

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3. if you were Rafaela will you also keep materials for the future? Why?

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Present the table:

10

2

2

10

20%

8

8

10

80%

Let the pupils identify rate, base and percentage.

The rate is the percent of the whole. It has the percent symbol (%).

The base is the whole we’re talking about. It is written after the word “of” or the phrase “percent of”

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The percentage is the portion of the whole based on the rate. It is usually followed by the word “is”.

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Using the Techan’s Triangle, ask them to determine the rate, base, and percentage

P

R

B

2

20%

10

If you were Rafaela will you also keep materials for the future? Why?

A. Let the pupils work in pair. Each pair works on every station simultaneously. Each of them will check their answers and present their output.�

Station 1: 5 is what percent of 50 What is the rate? ______�Station 2: 40% of 60 is what?� What is the percentage? ______�Station 3: 16 is 25% of 64� The base is ________�Station 4: 15% of total sales is P 8 910.� The rate is ________�Station 5: 43% of 150 is 64.5� The base is __________ �

Let the class the class check their answers by pairs and present their outputs one at a time. After all pairs have presented, ask “What is the meaning of percentage?Rate?� �Base? How will you determine the base in a given problem? The rate?and the �Percentage?

Say: The percentage is the portion of the whole based on the rate. It is usually followed� By the word “is”. The rate is the percent of the whole. It has the percent symbol (%).

The base is the whole we are talking about. It is written after the word “of” or the phrase “percent of”.

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Summarizing the Lesson� What is the meaning of percentage? Rate?Base?�

Percentage is a part of a whole. It is the resulting fractional part of the base. Rate is the number written with the word “percent” or with the symbol “%”. Base is the total or whole and it is the number that usually follows the phrase “percent of” or “% of”.

Assessment:�

Encircle the letter of the correct answer.

1. When one finds what percent one number is of another, we looks for the______.

a. base c. percentage

b. rate d. ratio

 2. Finding a number when a percent of it is known means solving for the _______

a. base c. percentage

b. proportion d. ratio

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3. 16 is 25% of 64. The percentage in the problem is __________.

a.16 b. 64 c.25% d. 41

4. Two of the 50 pieces of tomatoes in the basket are rotten. This is 4% of all the tomatoes In the basket. Which is the rate?

a. 50 b. 4% c. 2 d. 48

5. Seven of the 35 boys in the class wear eyeglasses. 20% of the boys wear eyeglasses. Which is the base?

a. 20% b. 7 c. 35 d. 40

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Home Activity� Identify the R, B, and P in the ff. statements:�

1. 180% of 200 is 360

2. 35% of 90 is 31.5 3. P100 is 4% of P2 500

4. 20% of 50 is 10

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