This was a real headscratcher but I finally got it.

The description for div x, y is "same with integer division" - integer being the key word we both missed.

Where i was wrong?

Program is:
mov a, 11 ; value1
mov b, 3 ; value2
call mod_func
msg 'mod(', a, ', ', b, ') = ', d ; output
end

; Mod function
mod_func:
mov c, a ; temp1
div c, b
mul c, b
mov d, a ; temp2
sub d, c
ret

My output is 0, but should be 2. How i know i am right but i have error there

It is what?

What's wrong? It's working.

Yes, it is

You can do it better:

def prod(arr):
if arr:
return max(accumulate(arr, mul))
return 1

Silly me, I forgot it works both ways

You also can change number*-1 to -number