\( ( \frac { 1 } { 2 } \pm \frac { 3 } { 20 } ) - \frac { 2 } { 20 } \)

To simplify the expression \( ( \frac { 1 } { 2 } \pm \frac { 3 } { 20 } ) - \frac { 2 } { 20 } \), let’s first convert \( \frac{1}{2} \) into a fraction with a denominator of 20, which gives us \( \frac{10}{20} \). Now we can rewrite the expression as: \[ ( \frac{10}{20} \pm \frac{3}{20} ) - \frac{2}{20} \] Using the "plus" sign, we calculate: \[ ( \frac{10 + 3}{20} ) - \frac{2}{20} = \frac{13}{20} - \frac{2}{20} = \frac{13 - 2}{20} = \frac{11}{20} \] Using the "minus" sign, we calculate: \[ ( \frac{10 - 3}{20} ) - \frac{2}{20} = \frac{7}{20} - \frac{2}{20} = \frac{7 - 2}{20} = \frac{5}{20} = \frac{1}{4} \] So the results for the expression are \( \frac{11}{20} \) when using the plus sign and \( \frac{1}{4} \) when using the minus sign.