Найдите разность: а) 4/5 - 3/4; в) 2/3 - 1/7; д) 5/6 - 5/12; б) 3/10 - 2/7; г) 5/9 - 1/3; е) 2/13 - 0.

а) $$4/5 - 3/4 = (4 \cdot 4)/(5 \cdot 4) - (3 \cdot 5)/(4 \cdot 5) = 16/20 - 15/20 = 1/20$$

в) $$2/3 - 1/7 = (2 \cdot 7)/(3 \cdot 7) - (1 \cdot 3)/(7 \cdot 3) = 14/21 - 3/21 = 11/21$$

д) $$5/6 - 5/12 = (5 \cdot 2)/(6 \cdot 2) - 5/12 = 10/12 - 5/12 = 5/12$$

б) $$3/10 - 2/7 = (3 \cdot 7)/(10 \cdot 7) - (2 \cdot 10)/(7 \cdot 10) = 21/70 - 20/70 = 1/70$$

г) $$5/9 - 1/3 = 5/9 - (1 \cdot 3)/(3 \cdot 3) = 5/9 - 3/9 = 2/9$$

е) $$2/13 - 0 = 2/13$$

Ответ: а) 1/20; в) 11/21; д) 5/12; б) 1/70; г) 2/9; е) 2/13