2. Вычислите: 1) $$4 \cdot \frac{5}{21}$$; 2) $$24 \cdot \frac{7}{12}$$; 3) $$\frac{16}{63} \cdot 9$$; 4) $$36 \cdot \frac{13}{48}$$;

1) $$4 \cdot \frac{5}{21} = \frac{4 \cdot 5}{21} = \frac{20}{21}$$ 2) $$24 \cdot \frac{7}{12} = \frac{24 \cdot 7}{12} = 2 \cdot 7 = 14$$ 3) $$\frac{16}{63} \cdot 9 = \frac{16 \cdot 9}{63} = \frac{16 \cdot 1}{7} = \frac{16}{7} = 2\frac{2}{7}$$ 4) $$36 \cdot \frac{13}{48} = \frac{36 \cdot 13}{48} = \frac{3 \cdot 13}{4} = \frac{39}{4} = 9\frac{3}{4}$$ Ответ: 1) $$\frac{20}{21}$$; 2) $$14$$; 3) $$2\frac{2}{7}$$; 4) $$9\frac{3}{4}$$