quiltingcandy

Do you want 140 squares all the same color? If so you will need 90 inches of fabric - or 2 yards and 18 inches = 2 1/2 yards.
Then you mention you want 28 more squares - is that another color? if so you will need 20 inches of that fabric.
Those numbers is assuming the fabric you get is straight and no room for error.

I have taken your number of 140 squares, fabric at 40 inches wide gives you 8 squares per strip. Divide 140 by 8 will tell you how many strips you will need = 17.5 so you will need 18 strips 5 inches wide = 90 inches.

for the 28 squares, divide 28 by 8 = 3.5 strips = 4 strips x 5 inches = 20.