The user enters the number of times to count , The program randomly generates five mixed operations of three digits ( Addition, subtraction, multiplication, division and modulo ), Such as 2+8x7=. The user enters the result , The program judges whether the user's result is correct , If the error returns the correct result . Finally, count the number of correct answers . Then ask whether to end or continue the next round of calculation . Be careful : If you encounter zero as divisor or zero as modulus, you should randomly generate a new operation . The operation priority is multiplication, division and modulo greater than addition and subtraction .