Question

Calcule as operações com frações: a) 2/3 + 4/3 b) 5/4 + 2/5 c) 3/8 + 5/6 + 10/9 d) 10/4 – 5/4 e) 18/3 – 15/6 f) 8/3 – 2/4 – 2/5 g) 12/4 x 3/2 h) 6/7 x 8/9 i) 2/5 x 1/3 x 3/4 j) 2/3 : 4/6 k) 9/5 : 5/8 l) 6/4: 2/7 x 5/9

Answer 1

Resposta:

$a)~\frac{2}{3}+ \frac{4}{3}- \frac{6}{3} =2\\ \\ b)~\frac{5}{4}+ \frac{2}{5}\\ \\ mmc=20\\ \\ \frac{25+8}{20}=\frac{33}{20}$

$c)~\frac{3}{8}+ \frac{5}{6}+ \frac{10}{9} =\\ \\ mmc~de~~~~~~8,~6,~9~|~2\\ ~~~~~~~~~~~~~~~~~~4,~3,~9~|~2\\ ~~~~~~~~~~~~~~~~~~2,~3,~9~|~2\\ ~~~~~~~~~~~~~~~~~~1,~3,~9~|~3\\ ~~~~~~~~~~~~~~~~~~~~~~1,~9~|~3\\ ~~~~~~~~~~~~~~~~~~~~~~~~~~3~|~3\\ ~~~~~~~~~~~~~~~~~~~~~~~~~~1\\ \\ 2^{3}~.~3^{3}=8~.~27=216\\ \\ \frac{81+180+240}{216} =\frac{501}{216}$

$d)~\frac{10}{4} -\frac{5}{4} =\frac{5}{4} \\ \\ e)~\frac{18}{3} -\frac{15}{6} =\\ \\ mmc=6\\ \\ \frac{36-15}{6} =\frac{21}{6}$

$f)~\frac{8}{3}- \frac{2}{4}- \frac{2}{5} =\\ \\ mmc~de~~3.~4,~5~|~2\\ ~~~~~~~~~~~~~3,~2,~5~|~2\\ ~~~~~~~~~~~~~3,~1,~5~|~3\\ ~~~~~~~~~~~~~~1,~1,5~|~5\\ ~~~~~~~~~~~~~~1.~1,~1~|\\ \\ 2^{2} ~.~3~.~5=60\\ \\ \frac{160-30-24}{60} =\frac{106}{60} =\frac{53}{30}$

$g)~\frac{12}{4}~.~ \frac{3}{2} =\frac{36}{8} =\frac{9}{2} \\ \\ h)~\frac{6}{7}~.~ \frac{8}{9} =\frac{48}{63} =\frac{16}{21}$

$i)~\frac{6}{4}: \frac{2}{7}~.~ \frac{5}{9} =\frac{6}{4}:\frac{10}{63} =\frac{6}{4}~.~ \frac{63}{10} =\frac{378}{40} =\frac{189}{20}$