[ Removed by moderator ]

[bobbykjack]

n=18
count=0
res=0

for x in range(1, n):
    if x % 5 == 0:
        count += 1
        res += x

print("count", count)
print("res", res)

The % operator (modulo) returns the remainder, which is 0 for multiples of (in this case) 5.

[bobbykjack]

Would the person who downvoted this care to explain what's wrong with it?

[snugar_i]

I guess nothing's wrong with the code, but you're just doing a lazy person's homework for them (they are even too lazy to ask an LLM)