Fractions must share a common denominator in order to be added or subtracted. The common denominator is the least common multiple of all the denominators.
What is \( \frac{2}{3} \) - \( \frac{9}{7} \)?
| \( \frac{2}{21} \) | |
| \( \frac{1}{5} \) | |
| -\(\frac{13}{21}\) | |
| \( \frac{7}{21} \) |