I have never done a number cake before.  What is the easiest way to do it?  I need the number 30.  I'm thinking either use some round cakes and piece them together or make a sheet cake and carve the numbers using a template.  

Also thinking I could get an oval cake pan and carve from there.  I don't want one of those weird number pans with the blocks in them because I don't think I would use it much and I don't like the squared number looks.

I'm also thinking I should keep it to 2 layers for the stability factor as it will not have fondant on it, only buttercream, and the numbers are thin (?).  But, I need a good 40 servings so I'm really not sure how big to make it.

Clearly this is not rocket science, but my brain is fried....and I need to write up a quote so I need to figure out how long this sucker is gonna take me :/

Use a 1/4 sheet to cut each number from. Cut numbers perhaps in a grafitti type font (big bubble) to maximize the servings (use most of the cake.) This will assure reaching desired number of servings.

Hmmm. that sounds easy.  Take 1/2 sheet, cut in half, ice & stack, then carve number. Yeah, that sounds much easier then pasting together round cakes.

Thank you @gigiel  per usual, I was overthinking things, haha!

Sheet cakes are great but a large oval pan would be really good for 30 too.

This might be helpful, just saw it on pinterest recently. https://preparedwithlovecaketoppers.wordpress.com/2013/10/01/how-to-create-easy-number-cakes-no-special-tins-required/

ouch -- this is painful -- i just tossed out all of my patterns yesterday including my number cake templates -- isn't there some kind of murphy's law that about that --

so anyway i vote for the bubble letters that gigiel proposed -- make sure the holes, nooks & crannies are accessible to your piping bags and spatulas -- a little bit bigger curves and angles can work out a little easier --

best to you

Round cakes are easiest for number 3 and 0 and have no wastage. 

Sorry. I mean the round ones with a hole in the middle....