1) 0,75 = 75/100 = 3/4
2,5 = 2 1/2
7,5 = 7 1/2
0,025 = 25 /1000 = 1/40
2,38 = 2 38/100 = 2 19/50
0,64 = 64/100 = 16/25
0,2 = 2/10 = 1/5
1,6 = 1 6/10 = 1 3/5
2) 3/4 - 1,75 = ,075 - 1,75 = -1
3/7 - 0,8 = 3/7 - 8/10 = 3/7 - 4/5 = 3*5 / 35 - 4*7/35 = (15-28)/35 = -13/35