1) 215 9/16 - 208 3/4 = 215 9/16 - 208 12/16 = 6 13/16

2) 6 13/16 + 1/2 = 6 13/16 + 8/16 = 6 21/16 = 7 5/16

3) 0,0001 : 0,005 = 0,02

4) 7 5/16 : 0,02 = 117/16 : 2/100 = 117/16 * 50/1 = 2925/8 = 365 5/8