# javascript - get number range

I'm not 100% sure how to ask this question so please dont mark me down for that.. I will do my best.

how do I work out what range my number falls in?

eg:

``var range = 100;var myNum = 320;``

Therfore my result would be `300` as that is the range 320 falls into.

further exampes would be:

``var range = 100;var myNum = 190;result: 100var range = 100;var myNum = 864;result: 800``

and lastly:

``var range = 50;var myNum = 864;result: 850``

Hope this make sence.

This is the logic you're looking for:

``````var result = range * Math.floor(myNum / range);
``````

Replace `Math.floor` by `Math.ceil` if you want to find the upper bound of the "range". The code above is an implementation of:

• How often does `range` suit in `range`?
• Multiply the previous result by `range`
• The final result equals the "number range".

You can also subtract from `myNum` the modulus of `myNum` by `range`:

``````var result = myNum - (myNum % range);
``````

`result = myNum - (myNum % range)`

myNum % range means "if I put range in my myNum as many times as I can, what integer will I have left?"

and you can subtract that from myNum and you get your result.