Question

(x-3 целых 13 двадцать первых)+ 2 целых 10 двадцать первых= 7 целых 2 двадцать первых

Answer 1

$(x-3 frac{13}{21}) +2 frac{10}{21} =7 frac{2}{21} \ x-3 frac{13}{21}=7 frac{2}{21}-2 frac{10}{21}\ x-3 frac{13}{21}=6 frac{23}{21} -2 frac{10}{21}\ x-3 frac{13}{21}=4 frac{13}{21}\ x=4 frac{13}{21}+3 frac{13}{21}\ x=7 frac{26}{21} =8 frac{5}{21} \ x=8 frac{5}{21}.$