Multiply the numerators, then multiply the denominators, then simplify.<br><br>
&bull; \( \frac{2}{7} \times \frac{21}{8} = \frac{2 \times 21}{7 \times 8} = \frac{42}{56} \)<br>
&bull; HCF of 42 and 56 is 14.<br>
&bull; \( \frac{42}{56} = \frac{42 \div 14}{56 \div 14} = \frac{3}{4} \)<br><br>
Final Answer: A = 3, B = 4