( 1 2/7 : 2 4/7 - 2/5 × 5/6) + 2 2/5: 2 2/15

Расставим действия:1 3 2 5 4(1 2/7 : 2 4/7 - 2/5 * 5/6) + 2 2/5 : 2 2/15 = (1/2 - 1/3) + 9/8 = 1/6 - 9/8 = 1 7/24;1) 1 2/7 : 2 4/7 = 9/7 : 18/7 = 9/7 * 7/18 = 1/2;2) 2/5 * 5/6 = 10/30 = 1/3;3) 1/2 - 1/3 = 3/6 - 2/6 = 1/6;4) 2 2/5 : 2 2/15 = 12/5 : 32/15 = 12/5 * 15/32 = 9/8;5) 1/6 + 9/8 = 4/24 + 27/24 = 31/24 = 1 7/24.