I want get closest number in the array. It have to be like this:

For example I have an array: `[1, 3, 7, 15, 40, 55, 70, 80, 95]`

Number variable: `numberD1`;

If numberD1: 8 - The closest number can be only 7. Not 15.

If numberD1: 54 - It can be only 40. Not 55.

I mean, i want closest number like this. But what I selected the number mustn't be higher than the closest number(like `Math.floor()` function).

Sorry for my Bad English. I hope i told my problem as good.