Algebra 1: Common Core (15th Edition)

The fractions have the same denominator (bottom of the fraction), so we can add and subtract them. Because 7/2 is negative, this is the same as subtracting 7/2 (because adding a negative is the same as subtraction). $\frac{1}{2}$-$\frac{7}{2}$=-$\frac{6}{2}=-3$