Understanding a Surprising Calculation

This video tutorial introduces a surprising calculation that always results in 8, regardless of the initial number chosen. The video walks through a series of mathematical steps, including subtraction, multiplication, addition, and division, to demonstrate this consistent outcome. It further explains the process using algebraic expressions and simplifies them to prove the result. The tutorial concludes by generalizing the calculation to work with any real number, not just counting numbers.

What is the first step in the surprising calculation process?

• Multiply the number by 3

• Add 12 to the number

• Think of any counting number

• Subtract 1 from the number

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CCSS.5.OA.A.1

CCSS.5.OA.A.2

In the calculation process, what do you do after subtracting 1 from your number?

• Divide the result by 3

• Multiply the result by 3

• Add 5 to the result

• Add 12 to the result

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CCSS.6.EE.B.6

What variable is used to represent the unknown counting number in the explanation?

• y

• z

• x

• a

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CCSS.7.EE.A.1

After simplifying the expression 3x - 3 + 12, what is the result?

• 3x - 9

• 3x + 12

• 3x + 9

• 3x + 3

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CCSS.7.EE.A.1

What is the result of dividing the expression 3x + 9 by 3?

• x + 8

• x + 5

• x + 3

• x + 9

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CCSS.6.EE.A.2A

What is the final result after subtracting the original number from x + 8?

• 5

• 8

• x

• 0

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CCSS.1.OA.A.1

What is the significance of the number 8 in this calculation?

• It is the number you subtract

• It is the result of the calculation

• It is the number you start with

• It is the number you add

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CCSS.5.OA.A.1

CCSS.5.OA.A.2

What is the final step in the calculation process?

• Add 5 to the result

• Subtract the original number

• Multiply by 3

• Divide by 3

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CCSS.5.OA.A.1

CCSS.5.OA.A.2

Can this calculation be applied to any real number?

• No, only to counting numbers

• Yes, to any real number

• No, only to integers

• Yes, but only to positive numbers

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CCSS.7.NS.A.1B