Post your code please.

sorry, but you can't post code without a spoiler tag, (which I've added for you), even if it's a partial or faulty solution. Also, it's important to use proper markdown formatting: https://github.com/Codewars/codewars.com/wiki/Markdown-Formatting, so people can more easily read your code. At first glace, it looks like you're having some off-by-one issues, so perhaps look into your rounding, either way it comes down to maths. good luck