Understanding Least Common Denominator

This video tutorial explains how to find the least common denominator (LCD) of fractions using the column method. It equates the LCD to the least common multiple (LCM) of the denominators. The tutorial provides two examples: one with denominators 18 and 27, and another with 24 and 30. Each example involves determining the prime factorization of the denominators, aligning the prime factors in columns, and calculating the product to find the LCD.

What is the Least Common Denominator (LCD) equivalent to?

• Highest Common Factor (HCF)

• Prime Factorization

• Least Common Multiple (LCM)

• Greatest Common Divisor (GCD)

What is the first step in the column method for finding the LCM?

• Aligning the prime factors

• Listing the numbers in ascending order

• Determining the prime factorization of the denominators

• Calculating the product of the numbers

What is the prime factorization of 18?

• 2 * 9

• 3 * 3 * 3

• 2 * 3 * 3

• 2 * 2 * 3

Tags

CCSS.4.OA.B.4

In the column method, where should the same prime factors be placed?

• In the first column

• In the same column

• In the last column

• In different columns

What is the least common denominator for the fractions 5/18 and 2/27?

• 81

• 54

• 36

• 72

What is the prime factorization of 24?

• 2 * 2 * 2 * 3

• 2 * 3 * 3

• 3 * 3 * 3

• 2 * 2 * 3

Tags

CCSS.4.OA.B.4

Which number is not a prime factor of 30?

• 5

• 3

• 6

• 2

How many columns are used in the prime factorization of 24 and 30?

• 3

• 4

• 6

• 5

What is the least common denominator for the fractions 7/24 and 11/30?

• 150

• 120

• 90

• 60

What is the final step in the column method for finding the LCM?

• Adding the prime factors

• Dividing the prime factors

• Subtracting the prime factors

• Multiplying the prime factors