Finding Percentages with Double Number Lines

This tutorial explains how to use a double number line to find 20% of 75. It involves setting up two number lines, one for 75 and another for 100, and dividing them into equal parts. By labeling these parts, the tutorial demonstrates how to calculate 20% of 75, showing that it equals 15. The concept of proportionality is highlighted, illustrating how double number lines can visually represent equivalent rates and help solve percentage problems.

What is the purpose of using a double number line in this tutorial?

• To measure the length of lines

• To find the percentage of a number

• To compare two unrelated quantities

• To draw a graph

What total value is assigned to the end of the second number line?

• 100

• 25

• 50

• 75

Tags

CCSS.2.NBT.B.7

How many equal parts is the number line divided into to find 20%?

• 4 parts

• 20 parts

• 5 parts

• 10 parts

What value is directly above 20% on the top number line?

• 10

• 15

• 20

• 25

What does each increment of 15 on the top number line represent?

• 1/2 of 75

• 1/3 of 75

• 1/5 of 75

• 1/4 of 75

Tags

CCSS.3.NF.A.1

CCSS.3.NF.A.2B

What fraction represents the relationship of 15 out of 75?

• 1/2

• 1/5

• 1/3

• 1/4

Tags

CCSS.3.NF.A.1

CCSS.3.NF.A.2B

How is 20% of 75 calculated using the double number line?

• By finding the value above 20 on the top line

• By multiplying 75 by 20%

• By adding 20 to 75

• By dividing 75 by 20

Tags

CCSS.6.RP.A.3C

What does the double number line graphically show?

• The difference between two quantities

• The multiplication of two quantities

• The sum of two quantities

• The proportional relationship between parts of two quantities

Tags

CCSS.7.RP.A.2D

Why are double number lines useful in mathematics?

• To graph functions

• To solve complex equations

• To find equivalent rates and unknown values

• To simplify addition problems

Tags

CCSS.7.RP.A.2D

What is the proportional relationship highlighted in the tutorial?

• 15 out of 75 is proportional to 20 out of 100

• 100 out of 75 is proportional to 20 out of 15

• 75 out of 100 is proportional to 20 out of 25

• 20 out of 75 is proportional to 15 out of 100

Tags

CCSS.7.RP.A.2A