Finding LCM by just multiplying the two numbers
"The Multiply Mistake"
The Mistake in Action
Find the LCM of 6 and 8.
Wrong: $6 \times 8 = 48$
Why It Happens
Students think "lowest common multiple" means the first multiple they can find, so they just multiply the numbers together.
The Fix
Multiplying gives a common multiple, but not necessarily the lowest.
$6 \times 8 = 48$ is a common multiple, but is it the lowest?
Check:
- Multiples of 6: 6, 12, 18, 24, 30, 36, 42, 48...
- Multiples of 8: 8, 16, 24, 32, 40, 48...
The lowest common multiple is 24, not 48.
Proper method: $6 = 2 \times 3$ $8 = 2^3$ LCM = $2^3 \times 3 = 24$
Spot the Mistake
Can you identify where this student went wrong?
Find the LCM of 6 and 8
$6 \times 8 = 48$
Click on the line that contains the error.
Related Topics
Learn more about the underlying maths: