Elementary Algebra

It takes 3$\frac{1}{4}$ yards of material to make one dress, which is equal to $\frac{13}{4}$. To make 20 dresses, we multiply $\frac{13}{4}$ by 20. So, $\frac{13}{4}$ $\times$ 20 = $\frac{13\ \times\ 20}{4}$ = Factor the numerator and the denominator: $\frac{13\ \times\ 4\ \times\ 5}{4}$ = Cancel the common factors in the numerator and the denominator to obtain: 13 $\times$ 5 = 65 yards of material