python sum of values ​​in a table

good evening everyone
I need a light with the following logic ..
I have two lists of tables with varying numbers
in the case of tables of different sizes

example
table 1
[‘1’, ‘142’, ’33’, ’33’, ‘9’, ‘2’]

table 2
[‘1′, ’12’, ‘7’, ‘-2′, ’39’, ’11’, ’31’, ’49’, ’50’, ‘1’]

how do I loop to sum the first element of Table 1 with the first element of Table 2
and so on, if you do not have the following element to complete the sum, the total must be zero

thus: 1 + 1, 142 + 12, 33 + 7 …

I know things about the loop and I practice
I do not see how to solve this example.