Can you list the options? so i can help, theres not enough info for me to answer
6 4/5 as improper fraction is 34/5
5 3/4 as improper fraction is 23/4
3 1/3 by 25/4 is 8/15
14/3 by 3 1/2 is 4/3
3 1/4 by 5 1/2 is 13/22
The numbers would be 1 and 6 you need to put the positive on the 6 and the negative on the 1 to get positive 5 when adding and -6 when multiplying
Hope this helps