28-(2/7+1/2)=

To solve the expression \( 28 - \left( \frac{2}{7} + \frac{1}{2} \right) \), we first need to calculate the sum inside the parentheses.

1. Find a common denominator for \( \frac{2}{7} \) and \( \frac{1}{2} \). The least common multiple of 7 and 2 is 14.

2. Convert each fraction:

   • \( \frac{2}{7} = \frac{2 \times 2}{7 \times 2} = \frac{4}{14} \)
   • \( \frac{1}{2} = \frac{1 \times 7}{2 \times 7} = \frac{7}{14} \)

3. Now, add the two fractions: \[ \frac{4}{14} + \frac{7}{14} = \frac{4 + 7}{14} = \frac{11}{14} \]

4. Now substitute this back into the original expression: \[ 28 - \frac{11}{14} \]

5. To subtract \( \frac{11}{14} \) from 28, we need to express 28 in terms of a fraction with a denominator of 14: \[ 28 = \frac{28 \times 14}{1 \times 14} = \frac{392}{14} \]

6. Now, perform the subtraction: \[ \frac{392}{14} - \frac{11}{14} = \frac{392 - 11}{14} = \frac{381}{14} \]

Thus, the result of the expression \( 28 - \left( \frac{2}{7} + \frac{1}{2} \right) \) is

\[ \frac{381}{14} \]

If you prefer a decimal, it is approximately \( 27.21428571428571 \).