40 : (19*13/17 - 3*13/17) + (5*3/5 - 2*4/5) : 7 = 3 61/130
1) 19*13/17 = 247/17
2) 3*13/17 = 39/17
3) 247/17 - 39/17 = 208/17
4) 40 : 208/17 = 40 * 17/208 = 680/208 = 3 56/208 = 3 7/26
5) 15/5 - 8/5 = 7/5
6) 7/5 : 7 = 7/5 * 1/7 = 7/35 = 1 /5
7) 3 7/26 + 1/5 = 3 35/130 + 26/130 = 3 61/130
