1. Evaluate (a) $\frac{1}{4} + \left(-\frac{3}{4}\right)$ Step 1: Add the fractions with common denominator 4. $$\frac{1}{4} + \left(-\frac{3}{4}\right) = \frac{1 - 3}{4}$$ Step 2: Simplify numerator. $$= \frac{-2}{4}$$ Step 3: Simplify fraction by dividing numerator and denominator by 2. $$= \frac{\cancel{-2}}{\cancel{4}} = -\frac{1}{2}$$ Final answer: $-\frac{1}{2}$ 2. Evaluate (a) $\frac{4}{5} \times \left(-\frac{20}{25}\right)$ Step 1: Multiply numerators and denominators. $$\frac{4 \times (-20)}{5 \times 25} = \frac{-80}{125}$$ Step 2: Simplify fraction by dividing numerator and denominator by 5. $$= \frac{\cancel{-80}}{\cancel{125}} = \frac{-16}{25}$$ Final answer: $-\frac{16}{25}$