This video tutorial explains how to subtract fractions using formal rules. It emphasizes the importance of having a common denominator and provides step-by-step instructions for subtracting fractions. Several examples are given, demonstrating both cases with and without a common denominator, and showing how to simplify the results. The tutorial also covers methods for finding the least common denominator and simplifying fractions using prime factorization.

Why is a common denominator necessary when subtracting fractions?

• To ensure the fractions are in simplest form

• To make sure the fractions have the same size parts

• To convert fractions into whole numbers

• To make the numerators equal

Tags

CCSS.5.NF.A.1

CCSS.5.NF.A.2

What is the first step in subtracting fractions with different denominators?

• Add the denominators

• Multiply the fractions

• Find the least common denominator

• Subtract the numerators directly

How can you simplify a fraction like four-eighths?

• By adding the numerator and denominator

• By dividing both by their greatest common factor

• By multiplying the numerator by two

• By subtracting the numerator from the denominator

What is the least common denominator of two-thirds and one-half?

• Three

• Twelve

• Six

• Nine

Tags

CCSS.3.NF.A.3B

CCSS.4.NF.A.1

How do you convert two-thirds to a fraction with a denominator of six?

• Multiply both numerator and denominator by two

• Subtract one from the denominator

• Add three to the numerator

• Multiply both numerator and denominator by three

Tags

CCSS.5.NF.A.1

CCSS.5.NF.A.2

What is the result of subtracting one-half from two-thirds?

• Three-sixths

• Two-sixths

• One-third

• One-sixth

What is the least common denominator of three-fourths and two-fifths?

• Twenty

• Fifteen

• Twenty-five

• Ten

Tags

CCSS.3.NF.A.3B

CCSS.4.NF.A.1

How do you convert three-fourths to a fraction with a denominator of twenty?

• Multiply both numerator and denominator by four

• Multiply both numerator and denominator by five

• Add five to the numerator

• Subtract four from the denominator

Tags

CCSS.4.NF.B.3C

CCSS.4.NF.B.3D

What is the simplified result of fifteen-twentieths minus eight-twentieths?

• Seven-tenths

• Seven-eighths

• Seven-fifteenths

• Seven-twentieths

What is the common factor between seven and twenty in the fraction seven-twentieths?

• Four

• Three

• Two

• One