Is null considered zero and undefined not a number on arithmetic expressions?

Question

Is null evaluated to 0 and undefined to NaN on arithmetic expressions?

According to some testing it seems so:

Answer 1

Without being type bound,

null == false == 0

null !== false !== 0

http://www.mapbender.org/JavaScript_pitfalls:_null,_false,_undefined,_NaN#0_6

With that said, null == 0, null + 4 = 4

I hope this helps.