Writing a code with 3 digit numbers while they cant contain 0 and then sum them

[AFKManager]

Hey i need to write a code for my teacher, he said Write a code that will have three 3digit numbers in it and if the number contains 0 f.e. 300,301 or so it will be removed. Afterwards i need to sum the numbers that are left.
So far i created a list with 3 variables in it a,b,c and before i defined a,b,c as random.randint(111,999) so it will be a 3 digit number.
My problem is that i dont know how to find a specific thing in a number. I tried changing the a to string and then doing if 0 in a: /nameoflist/.remove(a) but idk

import random
a=[random.randint(111,1000)]
b=[random.randint(111,1000)]
c=[random.randint(111,1000)]
cisla=[a,b,c]
str(a)
if 0 in a:
    cisla.remove(a)
print(cisla)

Note: cisla is name of list and in english it means numbers so u wont get confused :D