(1 17/18*1 13/14-2 5/8: 1 19/20): (2 25/78-1 1/26) решить пример

1) 1 17/18 * 1 13/14 = 35/18 * 27/14 = 45/12
2) 2 5/8 : 1 19/20 = 21/8 : 39/20 = 21/8 * 20/39 = 35/26
3) 45/12 - 35/26 = 585/156 - 210/156 = 375/156
4) 2 25/78 - 1 1/26 = 181/78 - 27/26 = 181/78 - 81/78 = 100/78
5) 375/156 : 100/78 = 375/156 * 78/100 = 15/8 =1 7/8