문제 12선택형1011×78=\frac{10}{11}\times\frac78=7087\frac{70}{87}3544\frac{35}{44}3144\frac{31}{44}1170\frac{11}{70}
문제 14선택형56×47=\frac56\times\frac47=221\frac{2}{21}621\frac{6}{21}821\frac{8}{21}1021\frac{10}{21}
문제 16선택형611×47=\frac{6}{11}\times\frac47=2477\frac{24}{77}1118\frac{11}{18}2425\frac{24}{25}1077\frac{10}{77}
문제 17선택형1112×89=\frac{11}{12}\times\frac89=1920\frac{19}{20}2227\frac{22}{27}1127\frac{11}{27}1027\frac{10}{27}
문제 18선택형78×59=\frac78\times\frac59=3572\frac{35}{72}1217\frac{12}{17}1172\frac{11}{72}3772\frac{37}{72}
문제 19선택형710×512=\frac{7}{10}\times\frac{5}{12}=824\frac{8}{24}724\frac{7}{24}624\frac{6}{24}524\frac{5}{24}
문제 20선택형57×38=\frac57\times\frac38=755\frac{7}{55}1555\frac{15}{55}955\frac{9}{55}1556\frac{15}{56}