To add fractions, both fractions have to have the same denominator.
For your problem, 1/2 + 1 = 1/2 + 2/2 = 3/2.
Here's a slightly harder problem: 1/2 + 1/3
The least common denominator is the least common multiple of 2 and 3, which is 6. So the common denominator will be 6. In a fraction, I can get the common denominator by multiplying by 1 in a suitable form. After the fractions have been rewritten using the common denominator, add the numerators and use the common denominator.
[tex]\frac{1}{2} + \frac{1}{3} = \frac{1}{2} * \frac{3}{3} + \frac{1}{3} * \frac{2}{2}[/tex]
[tex]=\frac{3}{6} + \frac{2}{6} = \frac{5}{6}[/tex]