4) -1/2 * 1/2 =

The problem asks to multiply two fractions, one of which is negative: \(-\frac{1}{2} \times \frac{1}{2}\).

1. Multiply the numerators: \(-1 \times 1 = -1\)
2. Multiply the denominators: \(2 \times 2 = 4\)
3. Combine the results: The resulting fraction is \(\frac{-1}{4}\).

Ответ: \(-\frac{1}{4}\)