(-3,7-2,4) - (7/15-2/8)-5,9
= - 12 13/60
1)- 3,7 - 2,4 = - 6,1
2)7/15 - 2/8 = 7/15 - 1/4 =(7 × 4 - 1 × 15)/60 = 28/60 - 15/60 = 13/60
3)-6,1 -13/60 =- 61/10 - 13/60 = (-61 × 6 - 13 × 1)/60 = -366/60 - 13/60 = - 379/60 = - 6 19/60
4)-6 19/60-5,9=-6 19/60-5 9/10=- 379/60 - 59/10 =(-379 × 1 - 59 × 6)/60 = -379/60 - 354/60 = - 733/60 = - 12 13/60