Mnożenie ułamków: $\frac{a}{b}\cdot \frac{c}{d}=\frac{a\cdot c}{b\cdot d}$, $b,d\ne 0$

---

Wykonajmy obliczenia.

a)

$1\frac{1}{3}\cdot \frac{2}{5}=\frac{4}{3}\cdot \frac{2}{5}=\frac{4\cdot 2}{3\cdot 5}=\frac{8}{15}$

---

b)

$3\frac{1}{2}\cdot \frac{3}{4}=\frac{7}{2}\cdot \frac{3}{4}=\frac{21}{8}=2\frac{5}{8}$

---

c)

$\frac{3}{7}\cdot 4\frac{3}{4}=\frac{3}{7}\cdot \frac{19}{4}=\frac{57}{28}=2\frac{1}{28}$

---

d)

$2\frac{4}{5}\cdot 3\frac{2}{3}=\frac{14}{5}\cdot \frac{11}{3}=\frac{14\cdot 11}{5\cdot 3}=\frac{154}{15}=10\frac{4}{15}$

---

e)

$1\frac{2}{3}\cdot 3\frac{1}{2}=\frac{5}{3}\cdot \frac{7}{2}=\frac{35}{6}=5\frac{5}{6}$

---

f)

$2\frac{1}{4}\cdot 3\frac{4}{5}=\frac{9}{4}\cdot \frac{19}{5}=\frac{171}{20}=8\frac{11}{20}$