ALTA Education
Cuisenaire Task Library
Multiples and Lowest Common Multiple
Your turn — Three numbers
Use the rods to find:
LCM(3, 4, 6)
Build trains using light green, pink and dark green rods.
- Find the first length at which all three trains line up.
- Record the equivalent trains using colour letters.
- Record the multiples that helped you find the answer.
- Write the answer using LCM notation.
- Now explain how you could find the answer without the rods.
Answers
The first common length is 12:
4g = 3p = 2d
LCM(3, 4, 6) = 12
Without rods, start with multiples of the largest number: 6, 12… Check each one for divisibility by both 3 and 4. Six is not divisible by 4; 12 is divisible by both.