${\Large\frac{7}{8}}+\left(-{\Large\frac{15}{16}}\right)={\Large\frac{14}{16}}+\left(-{\Large\frac{15}{16}}\right)=-\left({\Large\frac{15}{16}}-{\Large\frac{14}{16}}\right)=-{\Large\frac{1}{16}}=-0{,}0625$

$-{\Large\frac{4}{9}}-\left(-{\Large\frac{5}{6}}\right)=-{\Large\frac{8}{18}}+{\Large\frac{15}{18}}={\Large\frac{15}{18}}-{\Large\frac{8}{18}}={\Large\frac{7}{18}}$

$7 {\Large\frac{3}{5}}=7 {\Large\frac{3~\cdot~2}{5~\cdot~2}}=7 {\Large\frac{6}{10}}=7{,}6$

$7 {\Large\frac{3}{5}}+(-19{,}44)=7{,}6+(-19{,}44)=-(19{,}44-7{,}6)=-11{,}84$

$AB=-3{,}1-(-8{,}5)=-3{,}1+8{,}5=5{,}4$

$-37-22=-(37+22)=-59$

$1)~ 1 {\Large\frac{5}{12}}-\left(-3 {\Large\frac{1}{3}}\right)=1 {\Large\frac{5}{12}}+3 {\Large\frac{4}{12}}=4 {\Large\frac{9}{12}}=4 {\Large\frac{3}{4}}$

$2) 4 {\Large\frac{3}{4}}+\left(-4 {\Large\frac{3}{8}}\right)=4 {\Large\frac{6}{8}}-4 {\Large\frac{3}{8}}={\Large\frac{3}{8}}=0{,}375$

Найдём число, обратное числу $1 {\Large\frac{3}{5}}$.

$1 {\Large\frac{3}{5}}={\Large\frac{8}{5}}$

Обратное число — ${\Large\frac{5}{8}}$.

$\left(-2{,}16-\left(-3 {\Large\frac{7}{50}}\right)\right)+{\Large\frac{5}{8}}$

$1) \left(-2{,}16-\left(-3 {\Large\frac{7}{50}}\right)\right)=-2{,}16+3{,}14=0{,}98$

$2)~ 0{,}98+{\Large\frac{5}{8}}=0{,}98+0{,}625=1{,}605$

Пусть координата точки $A$ равна $a$, тогда:

$a-51=-42$

$a=-42+51=9$

Пусть координата точки $B$ равна $b$, тогда:

$b+39=9$

$b=9-39=-30$

Пусть координата точки $C$ равна $c$, тогда:

$c+39=-30$

$c=-30-39=-69$