Understanding Fraction Multiplication

Ken and Isaiah are trying to calculate how much pie they and their friends have eaten. Ken incorrectly multiplies 2/5 by 7, resulting in 14/35, which Isaiah points out is incorrect. The video explains the error and demonstrates the correct method, showing that the correct answer is 14/5 or 2 and 4/5 pies.

What was Ken's initial approach to solving the problem of how much pie was eaten?

• He divided the total pie by the number of people.

• He multiplied the fraction of pie each person ate by the number of people.

• He added the fraction of pie each person ate.

• He subtracted the fraction of pie each person ate from the total pie.

Tags

CCSS.5.NF.B.5B

Why did Isaiah find Ken's result suspicious?

• Because the result was more than one whole pie.

• Because the result was exactly one whole pie.

• Because the result was less than one whole pie.

• Because the result was a negative number.

Tags

CCSS.5.NF.B.6

What mistake did Ken make in his calculation?

• He added the fractions instead of multiplying.

• He multiplied both the numerator and denominator by 7.

• He divided the fractions incorrectly.

• He forgot to multiply the fractions.

Tags

CCSS.4.NF.B.4B

CCSS.4.NF.B.4C

How should Ken have correctly multiplied the fraction by 7?

• By adding 2/5 seven times.

• By dividing 2/5 by 7.

• By subtracting 2/5 from 7.

• By multiplying 2/5 by 1.

Tags

CCSS.4.NF.B.4B

CCSS.4.NF.B.4C

What is the correct result of multiplying 2/5 by 7?

• 2/5

• 14/5

• 7/5

• 14/35

How can the result 14/5 be expressed as a mixed number?

• 2 and 4/5

• 1 and 4/5

• 3 and 4/5

• 4 and 4/5

Tags

CCSS.4.NF.B.4B

CCSS.4.NF.B.4C

What is the equivalent of multiplying a fraction by a whole number?

• Adding the fraction to itself the number of times equal to the whole number.

• Dividing the fraction by the whole number.

• Subtracting the fraction from the whole number.

• Multiplying the fraction by zero.

Tags

CCSS.5.NF.B.5B

Which explanation correctly identifies Ken's mistake?

• Ken didn't multiply correctly; he should have added 2/5 seven times.

• Ken multiplied correctly but forgot to cancel out the 7s.

• Ken is correct; his friends didn't eat that much pie.

• Ken should have added 7 and 2/5 instead of multiplying.

Tags

CCSS.5.NF.B.5B

Why is explanation B incorrect?

• Because 2/5 times 7 is not the same as 2/5 times 1.

• Because Ken should have divided instead of multiplying.

• Because Ken should have added 7 and 2/5.

• Because Ken's friends ate more pie than calculated.

Tags

CCSS.5.NF.B.5B

What is the final correct explanation for the problem?

• Ken is correct; his friends didn't eat that much pie.

• Ken multiplied correctly but forgot to cancel out the 7s.

• Ken should have added 7 and 2/5 instead of multiplying.

• Ken didn't multiply correctly; he should have added 2/5 seven times.

Tags

CCSS.5.NF.B.5B