Fractions 8 – Three Methods for Finding the Lowest Common Multiple | Math Fluency

🔑 Key Ideas in Fractions 8 – Three Methods for Finding the Lowest Common Multiple | Math Fluency

There are three methods for finding the LCM.

• List of multiples
• The shortcut
• The Magic Question

In Box A, students find the LCM of 4 and 8. The first method involves listing the multiples of both 4 and 8, then finding the common multiples, then finding the lowest common multiple.

When using the shortcut, you do not need to list the multiples of both 4 and 8. Only list the multiples of the larger number, one at a time. As shown in the demo video, you get the same result for the LCM, but the amount of work is greatly reduced.

The Magic Question involves asking whether you can divide the larger number by the smaller number. If the answer is “yes,” then that larger number is the LCM. The Magic Question is the shortest and most efficient method.
The Magic Question does not always work. If it does not work, use the shortcut instead.