An interesting work with numbers

[Peter]

@app_inventor3

1 * 2 * 3 * 4 * 5 ... 99 * 100 =?

Recursion help or help with procedure result

I want to write a factorial routine using recursion but don't understand the procedure result block. essentially i want to see if n=1 then return 1 else return n*f(n-1) i am going crazy trying to do this in appinventor syntax. can anyone give a quick example? thanks!