1- Effectue les calculs suivants: \[ \begin{array}{ll} \frac{2}{7} \times \frac{4}{9}=\ldots & \frac{3}{8} \times 1=\ldots \\ \frac{4}{5} \times \frac{5}{4}=\ldots & \frac{4}{9} \times 0=\ldots \\ 2 \frac{3}{7} \times \frac{1}{2}=\ldots & \frac{2}{11} \times \frac{199}{199}=\ldots \\ \frac{7}{9} \times \frac{7}{9}=\ldots & 4 \frac{3}{7} \times 3 \frac{1}{5}=\ldots \\ \frac{2}{3} \times \frac{1}{10}=\ldots & 6 \frac{1}{2} \times \frac{2}{13}=\ldots \end{array} \] 2- Calcule les quotients suivants: \[ \begin{array}{l} \text { 2- Calcule les quotients suivants. } \\ \frac{5}{8} \div 4=\ldots \\ \frac{4}{9} \div 2 \frac{1}{4}=\ldots \\ 12 \frac{1}{9} \div 1 \frac{3}{4}=\ldots \\ \frac{2}{3} \div 10=\ldots \\ 2 \frac{8}{9} \div 4 \frac{4}{9}=\ldots \end{array} \]

Step 1 ：\(\frac{2}{7} \times \frac{4}{9} = \frac{2 \times 4}{7 \times 9} = \frac{8}{63}\)

Step 2 ：\(\frac{3}{8} \times 1 = \frac{3}{8}\)

Step 3 ：\(\frac{4}{5} \times \frac{5}{4} = \frac{4 \times 5}{5 \times 4} = 1\)

Step 4 ：\(\frac{4}{9} \times 0 = 0\)

Step 5 ：\(2 \frac{3}{7} \times \frac{1}{2} = \frac{17}{7} \times \frac{1}{2} = \frac{17}{14}\)

Step 6 ：\(\frac{2}{11} \times \frac{199}{199} = \frac{2}{11}\)

Step 7 ：\(\frac{7}{9} \times \frac{7}{9} = \frac{7 \times 7}{9 \times 9} = \frac{49}{81}\)

Step 8 ：\(4 \frac{3}{7} \times 3 \frac{1}{5} = \frac{31}{7} \times \frac{16}{5} = \frac{31 \times 16}{7 \times 5} = \frac{496}{35}\)

Step 9 ：\(\frac{2}{3} \times \frac{1}{10} = \frac{2 \times 1}{3 \times 10} = \frac{2}{30} = \frac{1}{15}\)

Step 10 ：\(6 \frac{1}{2} \times \frac{2}{13} = \frac{13}{2} \times \frac{2}{13} = 1\)

Step 11 ：\(\frac{5}{8} \div 4 = \frac{5}{8} \times \frac{1}{4} = \frac{5}{32}\)

Step 12 ：\(\frac{4}{9} \div 2 \frac{1}{4} = \frac{4}{9} \times \frac{4}{9} = \frac{16}{81}\)

Step 13 ：\(12 \frac{1}{9} \div 1 \frac{3}{4} = \frac{109}{9} \times \frac{4}{7} = \frac{436}{63}\)

Step 14 ：\(\frac{2}{3} \div 10 = \frac{2}{3} \times \frac{1}{10} = \frac{2}{30} = \frac{1}{15}\)

Step 15 ：\(2 \frac{8}{9} \div 4 \frac{4}{9} = \frac{26}{9} \times \frac{9}{40} = \frac{13}{20}\)