Question

Using only whole numbers, how can you draw three rectangles with perimeter of 12 units

Answer 1

Perimeter means the sides add up to 12. 
Rectangles have two pairs of equal sides. 

2(one side) + 2(another side) = 12
2 (one side + another side) = 12 
(one side + another side) = 6 

To draw a rectangle with a perimeter of 12 units, the two adjacent sides must add up to 6. 
1 + 5
2 + 4 
3 + 3