Rectangular tiles measuring 12 cm by 18 cm are placed side by side, all in the same direction, to form a square. What is the least number of tiles needed?

Explanation

1. 01

   The side of the square must be a multiple of both 12 and 18: $\operatorname{LCM} = 36$ cm.

2. 02

   Tiles along one side = $36 \div 12 = 3$; along the other = $36 \div 18 = 2$.

3. 03

   Number of tiles = $3 \times 2 = 6$.