4. Reconstituiți lanţul de calcule:

[tex] \frac{1}{3} \times \frac{3}{4} = \frac{4}{12} \times \frac{9}{12} = \frac{1}{4} \times \frac{3}{3} = \frac{1}{4} \times 1 = \frac{1}{4} [/tex]
[tex] \frac{1}{4} \times \frac{4}{5} = \frac{5}{20} \times \frac{16}{20} = \frac{80}{20} = 4[/tex]
[tex]4 \times \frac{5}{6} = \frac{20}{6} = \frac{10}{3} [/tex]
[tex] \frac{10}{3} \times \frac{6}{7} = \frac{70}{21} \times \frac{18}{21} = \frac{10}{7} \times \frac{6}{3} = \frac{10}{7} \times 2 = \frac{20}{7} [/tex]
Răspuns final: [tex] \frac{20}{7} [/tex]