A few probability problems...

I'm stumped on these questions I have no idea how to figure them out. Any help at all would be greatly appreciated. :)

1. A mountain search and rescue team receives an average of .83 calls per day. Find the probability that on a randomly selected day, they will receive more than two calls.

2. For a type of fabric, the average number of defects in each square foot is .78. Find the probability that a randomly selected square foot of fabric will contain more than 1 defect.

3. A sample of 4 different calculators are randomly selected from a group containing 13 that are defective and 30 with no defects. What is the probability that at least one of the calculators is defective?

Thanks for the help!