Now you've had a chance to count in 5s, have you spotted the pattern yet?
Did you figure out why we have a pattern? What happens when you add 2 fives? You get 10. So when you count in 5s every other number is going to end in 0 because 2 fives make a multiple of 10!
This is why we have the number pattern of 5, 0, 5, 0, 5, 0
Don't forget to use the Splat Square if you can to highlight the pattern. This will help you complete the sheet.