There are 3 yellow skittles, 2 green skittles, and 4 red skittles.
1. What is the ratio of red skittles to yellow skittles? ______________________
2. What is the ratio of green skittles to yellow skittles? _____________________
3. What is the ratio of green skittles to total number of skittles? _______________________
4. What is the ratio of yellow skittles to red skittles?