Odpowiedź:
[tex]a)\\\\\dfrac{7}{9}\cdot\dfrac{5}{14}=\dfrac{\not7^1\cdot5}{9\cdot\not14_{2}}=\dfrac{1\cdot5}{9\cdot2}=\dfrac{5}{18}\\\\\\b)\\\\\dfrac{4}{15}\cdot\dfrac{5}{8}=\dfrac{\not4^1\cdot\not5^1}{\not15_{3}\cdot\not8_{2}}=\dfrac{1\cdot1}{3\cdot2}=\dfrac{1}{6}\\\\\\\dfrac{3}{28}\cdot\dfrac{7}{12}=\dfrac{\not3^1\cdot\not7^1}{\not28_{4} \cdot\not12_{4}}=\dfrac{1\cdot1}{4\cdot4}=\dfrac{1}{16}[/tex]
