Respostas

2014-05-01T08:54:03-03:00
A)  \frac{1}{4} + \frac{1}{5} = \frac{5+4}{20} = \frac{9}{20}

b)  \frac{3}{5} + \frac{1}{3} = \frac{9+5}{15} = \frac{14}{15}

c)  \frac{1}{8} + \frac{1}{4} = \frac{1+2}{8} = \frac{3}{8}

d)  \frac{4}{7} + \frac{1}{3} = \frac{12+7}{21} = \frac{19}{21}

e)  \frac{2}{5} + \frac{1}{10} = \frac{4+1}{10} = \frac{5:5}{10:5} = \frac{1}{2}

f)  \frac{5}{6} - \frac{2}{3} = \frac{5-4}{6} = \frac{1}{6}

g) 1 - \frac{3}{4} = \frac{4-3}{4} = \frac{1}{4}

h) 3 - \frac{7}{8} = \frac{24-7}{8} = \frac{17}{8}

i)  1\frac{1}{7} - \frac{4}{5} =  \frac{8}{7} - \frac{4}{5} = \frac{40-28}{35} = \frac{12}{35}

j) 2\frac{5}{6} - \frac{4}{3} =  \frac{17}{6} - \frac{4}{3} = \frac{17-8}{6} = \frac{9:3}{6:3} = \frac{3}{2}
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