mew 4 u

Integers in Mew are as you would expect - just integers. Type one into the REPL and it'll spit it straight back out.

> 1
1

The same goes for floats.

> 1.0
1

And if you're in any doubt as to which is which, you can ask.

> type 1
.integer
> type 1.0
.float

From which we can deduce that function application in Mew is prefix. No, really:

> type (+ 1 1.0)
.float

And that operations on integers and floats cast upwards. Oh, and brackets denote precedence. As usual.