Let's call the parameter something generic to avoid confusion. We could remove some duplication here, too:

```coffeescript
.action (value, options) ->
  tutor.card (if +value is +value then +value else value),
             formatters.card[options.format]
```

We can check whether `value` is numeric by coercing it to a number and seeing whether the result is NaN (`x is x` is true for all values of x except NaN). We can then pass tutor.card a number or a string as appropriate and let it do the right thing.