Задача 39372 ...

sova

2019-09-11 21:13:14

★

1)
[m]\frac{5}{18}-\frac{7}{12}\cdot 0,5=\frac{5}{18}-\frac{7}{12}\cdot \frac{1}{2}=\frac{5}{18}-\frac{7}{24}=\frac{20}{72}-\frac{21}{72}=-\frac{1}{72}[/m]

[m]-\frac{1}{72}:\frac{5}{18}=-\frac{1}{72}\cdot\frac{18}{5}=-\frac{1}{20}[/m]

[m]-\frac{1}{20}-\frac{2}{3}=-\frac{3}{60}-\frac{40}{60}=-\frac{43}{60}[/m]

2)
-6,5-(4,2-6,5)=-6,5-4,2+6,5=-4,2

-4,2+[m]\frac{5}{21}\cdot \frac{2}{3}=-\frac{42}{10}+\frac{10}{63}=\frac{-42\cdot63+10\cdot10}{630}=[/m]