1. 1 ( (3+8-7)/4 = 4/4 = 1)

2. 4,5 ( (13-4)/2 = 9/2 = 4,5)

3. 4,625 ( (45+10-18)/8 = 37/8 = 4,625)

4. 9/19 ( (87-78)/19 = 9/19)

1. 1

2. 9/2 = 4,5

3. 37/8 = 4,625

4. 9/19 = 0,47………