10) -7/9 * 2/21 =

The problem asks to multiply two fractions, one of which is negative: \(-\frac{7}{9} \times \frac{2}{21}\).

1. Simplify before multiplying: Notice that 7 is a factor of 21. Divide both 7 and 21 by 7. So, \(-\frac{7{\div}7}{9} \times \frac{2}{21 {\div}7}\) becomes \(-\frac{1}{9} \times \frac{2}{3}\).
2. Multiply the numerators: \(-1 \times 2 = -2\)
3. Multiply the denominators: \(9 \times 3 = 27\)
4. Combine the results: The resulting fraction is \(\frac{-2}{27}\).

Ответ: \(-\frac{2}{27}\)