Hi,

• having several output types is a very bad idea
• having numbers handled as strings is a very bad idea as well (because of rouding problems, even if not that critical here). Tho that already leads to some shenanigans, as you can see, because the rounding troubles show up as soon as someone doesn't use the exact same way than you use.
• I think it's too close to a lot of other kata we already have (boils down to "nothing new here" and "the task is more tedious than interesting")
• the random assertions must be wrapped by a it block, not a describe one.

cheers