Question

вычислите рациональным способом​

Answer 1

$\displaystyle\bf\\1)\\\\5,45\cdot\frac{6}{19} +4,55\cdot\frac{6}{19} =\frac{6}{19}\cdot\underbrace{\Big(5,45+4,55\Big)}_{10}= \frac{6}{19} \cdot10=\frac{60}{19} =3\frac{3}{19} \\\\2)\\\\13,22\cdot\frac{15}{16} +\frac{1}{16} \cdot13,22=13,22\cdot\underbrace{\Big(\frac{5}{16} +\frac{1}{16} \Big)}_{1}=13,22\cdot 1=13,22\\\\3)\\\\\frac{3}{11} \cdot2\frac{7}{9}-\frac{7}{9} \cdot \frac{3}{11} =\frac{3}{11} \cdot\underbrace{\Big(2\frac{7}{9} -\frac{7}{9}\Big) }_{2}=\frac{3}{11} \cdot2=\frac{6}{11}$

$\displaystyle\bf\\4)\\\\8\frac{4}{71} \cdot\frac{3}{13} +\frac{3}{13} \cdot1\frac{67}{71} =\frac{3}{13} \cdot\underbrace{\Big(8\frac{4}{71} +1\frac{67}{71} \Big)}_{10}=\frac{3}{13}\cdot10=\frac{30}{13}=2\frac{4}{13}$