[tex] \bf \cfrac{1}{4}\div \cfrac{3}{8}\implies \cfrac{1}{4}\cdot \cfrac{8}{3}\implies \cfrac{8}{4}\cdot \cfrac{1}{3}\implies \cfrac{2}{1}\cdot \cfrac{1}{3}\implies \cfrac{2}{3} [/tex]
With experience you'll learn to see quickly what the LCD should be in situations like this. Here, 1/4 becomes 2/8, which has the same denominator as does 3/8.
Dividing 2/8 by 3/8 results in 2/3; the "8" in each of the two fractions cancels.
