Validate decimals on quarter values

Question

I have a decimal field which should allow only quarter values: 1.0, 1.25, 1.5, 1.75, but not values like 1.33 or 1.78. How can I validate this?

Answer 1

Another solution

(num % 0.25).zero?

Answer 2

To match such number use regex pattern

(?!0\d)\d+(?:[.](?:25|5|75|0)0*)?(?!\d)

Hope this regex could help