1) 1/25 * 4 = 4/25
2)4/25 - 4,41=0,16-4,41=-(4,41-0,16)= -4,25
3)2 5/18 - 5 1/12= 41/18-61/12=82/36-183/36=-101/36= -2 29/36
4)-2 29/36 + 1 2/9 = - (2 29/36 - 1 8/36) = -1 21/36= -1 7/12
5)-4,25 : 0,5= - (42,5:5) = - 8,5
6)3,8:(-1 7/12) =-(38/10 : 19/12) = - (38*12/10*19)= - 228/95 = - 2 38/95 = -2,4
7) -8,5 + 2,9 = -(8,5-2,9)= -5,6
8)-5,6 + (-2,4)= -8