Решите плизкки сам даун ничего не понимаю(

1)
$2{1\over3}*9={7\over3}*3*3=21\\1{1\over3}*3{1\over4}={4\over3}*{12\over4}=4\\2{2\over7}*3{5\over24}={16\over7}*{77\over24}={22\over3}=7{1\over3}\\21-4-7{1\over3}=9{2\over3}$

2)
$1{7\over48}*2{2\over5}={55\over48}*{12\over5}={11\over4}=2{3\over4}\\9{1\over6}*{4\over15}={55\over6}*{4\over15}={22\over9}\\{22\over9}+2{5\over9}={45\over9}=5\\5*{2\over5}=2\\2{3\over4}-2={3\over4}$

3)
$2{1\over4}+4{5\over6}={54\over24}+{116\over24}={170\over24}={85\over12}\\{85\over12}:3{2\over5}={85\over12}*{5\over17}={25\over12}\\{3\over4}:{3\over5}={15\over12}\\{25\over12}-{15\over12}={10\over12}={5\over6}$

4)
$4{2\over5}*{5\over8}={22\over5}*{5\over8}={11\over4}\\12{3\over7}:4{5\over6}={87\over7}*{6\over29}={18\over7}\\8{1\over2}:14={17\over28}\\{18\over7}-{17\over28}={72\over28}-{17\over28}={55\over28}\\{11\over4}+{55\over28}=11*({7\over28}+{5\over28})={33\over7}\\{33\over7}:{33\over56}=8$

5)
$3.04:{1\over30}=91.2\\16.03:{7\over20}=2.29*20=45.8\\91.2-45.8=45.4=45{2\over5}\\45{2\over5}*{1\over5}=9{2\over25}=9.08\\0.072*{1\over3}=0.024\\9.08+0.024=9.104$