Mastering Multiplication and Division of Rational Numbers

The video tutorial covers the multiplication and division of rational numbers, including fractions and mixed numbers. It explains how to multiply fractions by multiplying numerators and denominators directly and simplifying the result. The tutorial also covers cross-canceling as an alternative method. For mixed numbers, it demonstrates converting them to improper fractions before multiplying. The division section introduces the concept of multiplicative inverses or reciprocals and explains the KFC (Keep, Flip, Change) method for dividing fractions. The tutorial provides examples to illustrate these concepts.

When multiplying fractions, what is the first step?

• Add the numerators and denominators

• Cross-cancel the fractions

• Convert to improper fractions

• Multiply the numerators and denominators straight across

Tags

CCSS.5.NF.B.6

What is the result of multiplying 3/4 by 5/6?

• 5/6

• 5/8

• 15/24

• 1/2

Tags

CCSS.5.NF.B.6

What is the purpose of cross-canceling when multiplying fractions?

• To find the reciprocal

• To convert fractions to mixed numbers

• To simplify the fractions before multiplying

• To add the fractions

Tags

CCSS.5.NF.B.6

What is the correct result of 3/4 multiplied by 5/6 after cross-canceling?

• 5/6

• 5/8

• 1/2

• 3/4

Tags

CCSS.5.NF.B.6

How do you convert a mixed number to an improper fraction?

• Multiply the numerator by the denominator

• Divide the numerator by the denominator

• Multiply the whole number by the denominator and add the numerator

• Add the whole number to the numerator

What is the improper fraction form of 2 1/3?

• 7/3

• 6/3

• 5/3

• 8/3

What is the multiplicative inverse of 1/5?

• 1/5

• 5

• 1

• 5/1

Tags

CCSS.3.NF.A.1

CCSS.3.NF.A.2B

What is the reciprocal of -3/8?

• -8/3

• 3/8

• 8/3

• -3/8

What does KFC stand for in dividing fractions?

• Keep, Flip, Cross

• Keep, Flip, Change

• Keep, Find, Change

• Keep, Find, Cancel

Tags

CCSS.6.NS.A.1

What is the result of dividing 5/4 by 4/15 using the KFC method?

• 20/60

• 1/3

• 15/4

• 5/4

Tags

CCSS.6.NS.A.1