Find a common multiple
common-multiple · skill · prompt: Find a common multiple of {x} and {y}.
| Method | Idea | Best when | Calls |
|---|---|---|---|
Know the LCM recall |
Recognize the least common multiple directly. | Small, familiar numbers. | — |
List multiples list_multiples |
Count up by {x} until you reach a number {y} divides. | Small numbers. | — |
Multiply them product |
{x} × {y} is always a common multiple. | The numbers share no factors (then it’s also the least). | — |
Use the GCF gcf_formula |
LCM = {x} ÷ GCF × {y}. | Large numbers whose GCF you can find. | — |
Each graph starts at the question and branches at × Which first step? into every first step a student might write. Methods that share a first step meet there and split at × Which next step?. Each route then follows its method to the answer. The legend at the bottom of each graph explains the shapes.
Find a common multiple of 4 and 6.
Find a common multiple of 4 and 7.
