I'm trying to get rough greater than and less than values to compare latitude and longitude. I need to be able to pass in a latitude, longitude and number of digits to which to round. If I have these values for example:

```
18.363285   -67.18024
18.448619   -67.13422        <----- Only second value matched
18.498987   -67.13699        <----- Both values matched 
18.465162   -67.141486
18.182151   -66.9588

```

Selecting the middle as one to match, I want to pass in 18.49(1234567) as latitude, -67.13(1234567) as longitude and **2** as the number of decimals to which to round. I'm planning to round the given latitude and longitude down by **2** places to get the lower bound, then add **0.02** to this to get the upper bound.

I'm stuck on the last part. I can't think of a mathematical function which takes 4 as an input and returns 0.00004.

Unless I'm overcomplicating this and there's a simple way to match a set of values within a tolerance.

EDIT: For example, I need to pass in these numbers and get these values back:

```
In   Out
1   0.01
2   0.001
3   0.0001
4   0.00001
5   0.000001
6   0.0000001

```