1. Выполните действие.

a) 12/35 × 7/18 = 84/630 = 14/105 = 2/15. b) 7/33 ÷ 7/18 = (7/33) × (18/7) = 18/33 = 6/11. c) 7/12 × 11/15 = 77/180. d) 7/48 × 9 = 63/48 = 21/16.