t = int(input())
for _ in range(t):
    a, b, c = map(int, input().split())
    if c <= 40:
        print(a * pow(10, c) // b % 10)
    else:
        c2 = 0
        while b % 2 == 0:
            b //= 2
            c2 += 1
        c5 = 0
        while b % 5 == 0:
            b //= 5
            c5 += 1
        t = a * pow(2, c - c2, b) * pow(5, c - c5, b) % b
        l = []
        for x in range(10):
            if (b * x + t) % 10 == 0:
                l.append(x)
        print(l[0])