Question

Вычислите обратив десятичную дробь в обыкновенную: в) 1/12+0,25; г) 5/6-0,1; д) 2/3+0,8; е) 0,4-16;

Answer 1

$\frac{1}{12}+0,25= \frac{1}{12} + \frac{25}{100}= \frac{1}{12}+ \frac{25*1}{25*4}=\frac{1}{12}+ \frac{1}{4}=\frac{1}{12}+ \frac{1*3}{12}= \frac{1+3}{12} =\frac{4}{12}=$$\frac{4*1}{4*3}=\frac{1}{3}$

$\frac{5}{6} -0,1= \frac{5}{6} - \frac{1}{10} = \frac{5*5}{6*5} - \frac{1*3}{10*3} = \frac{25}{30} - \frac{3}{30}= \frac{25-3}{30}=\frac{22}{30}=\frac{11*2}{15*2}= \frac{11}{15}$

$\frac{2}{3} +0,8= \frac{2}{3} + \frac{8}{10}=\frac{2}{3} + \frac{4*2}{5*2}=\frac{2}{3} + \frac{4}{5}= \frac{2*5}{3*5} + \frac{4*3}{5*3} = \frac{10+12}{15} =\frac{22}{15} =1 \frac{7}{15}$

$0,4- \frac{1}{6}= \frac{4}{10} - \frac{1}{6}= \frac{4*3}{10*3}- \frac{1*5}{6*5}= \frac{12-5}{30}= \frac{7}{30}$