(1 17/18 * 1 13/14 -1 19/20 ) :( 2 25/78 - 1 1/26) =1,404
1) 1 17/18 * 1 13/14 = 15/4 = 3,75
2) 3,75 - 1 19/20 = 3,75-1,95 = 1,8
3) 2 25/78 - 1 1/26 = 2 25/78 - 1 3/78 = 1 22/78 = 1 11/39
4) 1,8 : 1 11/39 = 1 4/5 : 1 11/39 = 9/5 * 39/50 = 351/250 = 1,404