Question: I have a configuration value stored as `3.months`, and another value returning from a calculation as `7.days`. 

I need to find their difference. What is the easiest & Railsiest way to normalise them so that I can subtract `7.days` from `3.months`? I can turn .months into days by using .to\_i & multiplying by seconds-in-a-day, but it feels pretty long-winded to have to calculate from months to seconds to days like this:

```
  x = (3.months.to_i/86400).days
  => 90 days
  x - 7.days
  => 83 days

```

Is there a snappier way?

Answer: 
If you want to keep each term with units of time I would recommend this:

```
 (3.months - 7.days)/1.day

```

I feel like its the cleanest and easiest for another dev to realize what you are trying to describe.
I'f I understand correctly, you can subtract them one from another like so:

```
(3.months - 7.days)/86400 #=> 83

```

Both months and days methods return an integer of seconds.