Exploring Adding and Subtracting Rational Expressions

This video tutorial teaches how to solve percentage problems mentally. It begins with a warmup exercise, followed by methods to calculate 5%, 10%, 15%, and 20% of given values. The video explains moving the decimal to find 10%, halving it for 5%, and doubling it for 20%. It also covers finding 15% by adding 5% and 10%. The tutorial concludes with application problems, demonstrating how to apply these techniques in real-world scenarios.

What is the first step in the exercise described at the beginning of the video?

• Write down the numbers

• Start the video from the beginning

• Pause the video and use a calculator

• Guess the percentages

How do you find 10% of a number mentally?

• Add 10% to the number

• Move the decimal point one place to the left

• Divide the number by 10

• Multiply the number by 0.1

Tags

CCSS.6.RP.A.3C

What is 20% of a number if 10% of it is known?

• Divide 10% by 2

• Multiply 10% by 2

• Subtract 10% from the number

• None of the above

Tags

CCSS.6.RP.A.3C

What is the correct method to calculate 20% of a number?

• Double the result of 10% of the number

• Subtract 10% from the number

• Halve the result of 10% of the number

• None of the above

Tags

CCSS.6.RP.A.3C

How can 5% of a number be calculated if 10% is known?

• None of the above

• Subtract 10% from itself

• Add 10% to itself

• Multiply 10% by 0.5

Tags

CCSS.6.RP.A.3C

What is the method to find 15% of a number?

• Add 10% and 5% of the number

• Multiply 10% by 1.5

• Subtract 5% from 20%

• Divide the number by 6.67

Tags

CCSS.6.RP.A.3C

If Joan uses 20% of his paycheck for bills and his paycheck is $572, how much does he spend?

• $114.40

• $228.80

• $57.20

• $114

Tags

CCSS.6.RP.A.3C

How much of the gummy bears does Blair have left after giving away 10%?

• 2.7 pounds

• 2.43 pounds

• 2.97 pounds

• 0.27 pounds

Tags

CCSS.6.RP.A.3C

How many calls did Nick's mother make if 15% of his 140 calls were from her?

• 21 calls

• 15 calls

• 140 calls

• 25 calls

Tags

CCSS.6.RP.A.3C

How much was donated to local schools from Sam's grocery bill of $82.60?

• $12.39

• $4.13

• $8.26

• $41.30

Tags

CCSS.6.NS.B.3