1,4-(3,5÷1 1/4)÷2,4+3,4÷2,8 = 1 47/105
3,5 ÷ 1 1/4 = 3,5 ÷ 5/4 = 3,5 ÷ 1,25 = 2,8
2,8 ÷ 2,4 = 2 8/10 ÷ 2 4/10 = 28/10 ÷ 24/10 = 14/5 ÷ 12/5 = 14/5 × 5/12 = 7/6 = 1 1/6
3,4 ÷ 2,8 = 3 4/10 ÷ 2 8/10 = 34/10 ÷ 28/10 = 17/5 ÷ 14/5 = 17/5 × 5/14 = 17/14 = 1 3/14
1,4 - 1 1/6 = 1 4/10 - 1 1/6 = 14/10 - 7/6 =7/5-7/6=(7 × 6 - 7 × 5)/30 = (42 - 35)/30 = 7/30
7/30 + 1 3/14 = 7/30 + 17/14 = (7 × 7 + 17 × 15)/210 = (49 + 255)/210 = 304/210 = 152/105 = 1 47/105