Помогите пожалуйста с тестом(С ПОЛНЫМ РЕШЕНИЕМ,НЕ ПРОСТО ОТВЕТЫ А ПОЯСНЕНИЕ,КАК РЕШАЛИ,И...

Решите задачу:

$1.\\a)\;5\frac12+1\frac16=5\frac36+1\frac16=\left(5+1\right)+\left(\frac36+\frac16\right)=6+\frac46=6+\farc23=6\frac23;\\\\b)\;2\frac49+3\frac12=2\frac8{18}+3\frac9{18}=(2+3)+\left(\frac8{18}+\frac9{18}\right)=5+\frac{17}{18}=5\frac{17}{18};\\\\c)\;5\frac7{12}+1\frac78=5\frac{14}{24}+1\frac{21}{24}=(5+1)+\left(\frac{14}{24}+\frac{21}{24}\right)=6+\frac{35}{24}=6+1\frac{11}{24}=7\frac{11}{24}$

$d)\;6\frac25-1\frac1{10}=6\frac4{10}-1\frac1{10}=(6-1)+\left(\frac4{10}-\frac1{10}\right)=5+\frac3{10}=5\frac3{10}\\\\e)\;4\frac57-1\frac23=4\frac{15}{21}-1\frac{14}{21}=(4-1)+\left(\farc{15}{21}-\frac{14}{21}\right)=3+\frac1{21}=3\frac1{21};\\\\f)\;3\frac12-1\frac23=3\frac36-1\frac46=(3-1)+\left(\frac36-\frac46\right)=2-\frac16=1\frac56.$

$2.\\15\frac12-\left(6\frac14+2\frac38\right)=\boxed{6\frac78}\\\\1)\;6\frac14+2\frac38=6\frac28+2\frac38=(6+2)+\left(\frac28+\frac38\right)=8+\frac58=8\frac58;\\\\2)\;15\frac12-8\frac58=15\frac48-8\frac58=(15-8)+\left(\frac48-\frac58\right)=7-\frac18=6\frac78.$