Question

Repede toate subpunctele

Answer 1

$e) \frac{1}{5} + \frac{7}{15} + \frac{5}{8} = \\ \\ \frac{1}{5} + \frac{7}{15} = \frac{1 \times 3}{5 \times 3} + \frac{7}{15} = \frac{3}{15} + \frac{7}{15} = \frac{3 + 7}{15} = { \frac{10}{15} }^{(5} = \frac{2}{3} \\ \\ \frac{2}{3} + \frac{5}{8} = \frac{2 \times 8}{3 \times 8} + \frac{5 \times 3}{8 \times 3} = \frac{16}{24} + \frac{15}{24} = \frac{16 + 15}{24} = \frac{31}{24} = 1 \frac{7}{24}$

$f) \frac{1}{4} + \frac{7}{24} + \frac{5}{8} = \\ \\ \frac{1}{4} + \frac{7}{24} = \frac{1 \times 6}{4 \times 6} + \frac{7}{24} = \frac{6}{24} + \frac{7}{24} = \frac{6 + 7}{24} = \frac{13}{24} \\ \\ \frac{13}{24} + \frac{5}{8} = \frac{13}{24} + \frac{5 \times 3}{8 \times 3} = \frac{13}{24} + \frac{15}{24} = \frac{13 + 15}{24} = { \frac{28}{24} }^{(4} = \frac{7}{6} = 1 \frac{1}{6}$

$g)3 + \frac{1}{4} + \frac{2}{5} = \\ \\ 3 + \frac{1}{4} = \frac{3}{1} + \frac{1}{4} = \frac{3 \times 4}{1 \times 4} + \frac{1}{4} = \frac{12}{4} + \frac{1}{4} = \frac{12 + 1}{4} = \frac{13}{4} \\ \\ \frac{13}{4} + \frac{2}{5} = \frac{13 \times 5}{4 \times 5} + \frac{2 \times 4}{5 \times 4} = \frac{65}{20} + \frac{8}{20} = \frac{65 + 8}{20} = \frac{73}{20} = 3 \frac{13}{20}$

$h) \frac{3}{11} + \frac{4}{3} + \frac{7}{12} = \\ \\ \frac{3}{11} + \frac{4}{3} = \frac{3 \times 3}{11 \times 3} + \frac{4 \times 11}{3 \times 11} = \frac{9}{33} + \frac{44}{33} = \frac{9 + 44}{33} = \frac{53}{33} \\ \\ \frac{53}{33} + \frac{7}{12} = \frac{53 \times 4}{33 \times 4} + \frac{7 \times 11}{12 \times 11} = \frac{212}{132} + \frac{77}{132} = \frac{212 + 77}{32} = \frac{289}{132} = 2 \frac{25}{132}$

$i) \frac{1}{5} - \frac{1}{7} = \frac{1 \times 7}{5 \times 7} - \frac{1 \times 5}{7 \times 5} = \frac{7}{35} - \frac{5}{35} = \frac{7 - 5}{35} = \frac{2}{35}$

$j) \frac{7}{20} - \frac{5}{18} = \frac{7 \times 9}{20 \times 9} - \frac{5 \times 10}{18 \times 10} = \frac{63}{180} - \frac{50}{180} = \frac{63 - 50}{180} = \frac{13}{180}$

$k) \frac{8}{13} - \frac{5}{39} = \frac{8 \times 3}{13 \times 3} - \frac{5}{39} = \frac{24}{39} - \frac{5}{39} = \frac{24 - 5}{39} = \frac{19}{39}$

$l)3 - \frac{2}{5} = \frac{3}{1} - \frac{2}{5} = \frac{3 \times 5}{1 \times 5} - \frac{2}{5} = \frac{15}{5} - \frac{2}{5} = \frac{15 - 2}{5} = \frac{13}{5} = 2 \frac{3}{5}$

Answer 2

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