奇數位總和減掉偶數位總和絕對值再%11看是不是等於0就好了

def solve(n):

    return f'{n} is a multiple of 11.' if abs(sum([int(i) for i in n[0::2]]) - sum([int(i) for i in n[1::2]])) % 11 == 0 else f'{n} is not a multiple of 11.'