How to use M-<Number> to type a digit?

Question

I came across this problem in below situation:
I am trying to enter fourty 0s. So I pressed:
M-40 0. However I ended up with four hundred instances of my next keystroke.
Is there a solution for this?

Answer 1

Use C-u to terminate the numeric prefix:

M-40 C-u 0

Answer 2

Try this (a C-u terminates the numeric argument):

C-u 40 C-u 0