Арифметические операции над числами

print('Какую операцию проводить с числами?')
print('(ввести: +, -, * или /):')
operation = input()
first_number = str(input('Введите первое число: '))
first_number = first_number[::-1]
second_number = str(input('Введите второе число: '))
second_number = second_number[::-1]
makeshift = str()
result = str()
 
if len(first_number) > len(second_number):
    makeshift = first_number
    first_number = second_number
    second_number = makeshift
    
calculate = 0
transposition = 0
if operation == '+':
    for i in range(0, len(second_number)):
        if i < len(first_number):
            calculate = int(first_number[i]) + int(second_number[i]) + transposition
        else:
            calcuate = int(second_number[i]) + transposition
        result += str(calculate % 10)
        transposition = calculate // 10
    result += str(transposition)
    result = result[::-1]
print(result)

a = '256'
b = '1024'
 
def plus(first, second):
    # after all, it well be reversed
    maxlen = max(len(first), len(second))
    minlen = min(len(first), len(second))
    zero_diff = '0' * (maxlen - minlen)
    if len(first) > len(second):
        second = zero_diff + second
    else:
        first = zero_diff + first
    # it will be reversed
    result_buf = [0] * (maxlen + 1)
 
    for pos, (ia, ib) in enumerate(list(zip(first, second))[::-1]):
        res = int(ia) + int(ib)
        if res < 10:
            result_buf[pos] += res
        else:
            result_buf[pos] += res - 10
            result_buf[pos+1] += 1
 
    result_buf.reverse()
    return ''.join(str(digit) for digit in result_buf)
 
 
print(plus(a, b))