1) 5.10-2.8.16. 10-1

Answer: - 2511 (if the periods mean multiplication)

Step-by-step explanation:

I'm not sure whether you're trying to have the periods be multiplication, but if that's what they are, this is the answer

5x10-2x8x16x10-1

50-16x160-1

50-2560-1

-2511

Again, I'm not sure if that's what you mean but I can't really see what else they would mean since you can't have a 3 part decimal