import time
import random
correctCount = 0  #Count the number of correct answers
count = 0 #Count the number of questions
startTime = time.time()*1000.0
while (count < 5):
    number1 = random.randint(1,16)
    number2 = random.randint(1,16)
    #Prompt the student to answer "what is number1 – number2?"
    print("What is  {}  -  {} ? ".format(number1,number2))
    answer = int(input())
    #Grade the answer and display the result
    if (number1 - number2 == answer):
        print( "You are correct!")
        correctCount=correctCount+1
    else:
        print("Your answer is wrong.\n {} - {}  should be".format(number1,number2), (number1 - number2))
    #Increase the count by incremeting variable called "count"
    count=count+1
print("Correct count is ",correctCount)
endTime = time.time()*1000.0
print("Time spent is  {} seconds".format((endTime - startTime) / 1000))
  

Output:

What is  4  -  14 ? 
-10
You are correct!
What is  4  -  9 ? 
-5
You are correct!
What is  16  -  4 ? 
12
You are correct!
What is  7  -  13 ? 
5
Your answer is wrong.
 7 - 13  should be -6
What is  1  -  6 ? 
4
Your answer is wrong.
 1 - 6  should be -5
Correct count is  3
Time spent is  28.8054658203125 seconds