In python:
numA = [4, 1, 6, 10, 2, 3, 7, 9, 11, 12, 5, 8]
numB = [2, 12, 10, 11, 1, 3, 7, 9, 4, 8, 5, 6]
while True:
    i = 0
    userChoice = input("Adding or Multiplying? (a/m) ")
    if userChoice == "a":
        while i < len(numA):
            answer = int(input("What is {} + {} ".format(numA[i],numB[i])))
            if answer == numA[i] + numB[i]:
                print("Correct!")
            else:
                print("That's incorrect. The right answer is {}".format(numA[i] + numB[i]))
            i += 1
    elif userChoice == "m":
        while i < len(numA):
            answer = int(input("What is {} * {} ".format(numA[i], numB[i])))
            if answer == numA[i] * numB[i]:
                print("Correct!")
            else:
                print("that's incorrect. The right answer is {}".format(numA[i] * numB[i]))
            i += 1