This is the Mneumonics for web assembly that can be quickly compiled to a WASM Module.

Boilerplate

(module
	(import "math" "callback" (func $callback))	
	(export "add" (func $add))
	(export "subtract" (func $subtract))
	(func $add (param $a i32) (param $b i32) (result i32)
		local.get $a
		local.get $b
		i32.add
	)
	(func $subtract (param $a i32) (param $b i32) (result i32)
		local.get $a
		local.get $b
		i32.sub
	)
)