Hello!
For 5, the answer is 0, as it asks you about the different ways you can say it below.
6)
1. Nil. Nil is a term used in sports that refers to zero.
2. Zero. Usually you will say 5 degrees below zero.
3. Oh. In phone numbers might say eight oh one.
4. Naught. As naught is the only option left after love, I believe it goes with math!
5. Love. Love is a tennis term, such as 15 to zero would be 15 love.
Hope this helps!