Finding LCM and GCF Concepts

The video tutorial explains how to find the lowest common multiple (LCM) and greatest common factor (GCF) of the numbers 42 and 56 using a factor tree method. It demonstrates organizing prime factors in a chart to avoid mistakes and provides step-by-step calculations for both LCM and GCF. The LCM is calculated as 168, and the GCF is 14. The tutorial concludes with a summary of the process and encourages viewers to subscribe for more math and science videos.

What is the purpose of using a factor tree in finding LCM and GCF?

• To add numbers quickly

• To identify prime factors

• To subtract numbers easily

• To divide numbers accurately

Which of the following is a prime factor of 42?

• 4

• 6

• 3

• 9

How many times does the number 2 appear as a prime factor in 56?

• Once

• Twice

• Three times

• Four times

Why is it important to organize numbers in a chart when finding LCM and GCF?

• To make calculations faster

• To avoid mistakes

• To use fewer numbers

• To increase complexity

What is the first step in calculating the LCM from the chart?

• Divide all numbers

• Bring down one of each common number

• Multiply all numbers

• Add all numbers

What is the LCM of 42 and 56?

• 210

• 168

• 126

• 84

What should you do if you have two of the same numbers in both 42 and 56 when finding the LCM?

• Add them together

• Bring one down

• Ignore one of them

• Multiply them

Which numbers are used to find the GCF of 42 and 56?

• Only 2

• 3 and 7

• Only 7

• 2 and 7

What is the GCF of 42 and 56?

• 14

• 21

• 7

• 28

What is the final step in finding the GCF?

• Add the numbers

• Divide the numbers

• Subtract the numbers

• Multiply the common factors