A Python Arithmetic Math Game

Question

Minor information: I am using a Lenovo Chromebook (Linux), CodePad (Text Editor), and Terminal (as a way to see the output).

Objective: I wanted to create a game-like program, where the computer generates random values between 0 to a 100 and generates a random operator, to add/subtract/multiply/divide with another random value between 0 to a 100. If you get the question correct, your score goes up by 1 and if it's wrong your score decreases by 1.

Problem: The program works good on all the operators except division. I want the division answer to be rounded to the nearest hundredths. For example: 23 / 54 = 0.42592592592. I want the program to accept it as 0.43.

Here's what I have: (Can someone edit my code below to Python, I'm not sure how).

from random import randint
import random
score = 0
while True:
    num1 = randint(0,100)
    num2 = randint(0,100)
    op = random.choice(["+", "-", "*", "/"])

    if op == '+':
        print(num1, "+", num2, "= x ")
        x_answer = num1 + num2

    elif op == '-':
        print(num1, '-', num2, '= x')
        x_answer = num1 - num2

    elif op == '*':
        print(num1, "*", num2, "= x")
        x_answer = num1 * num2

    elif op == "/":
        print(num1, "/", num2, "= x")
        x_answer = num1 / num2

    else:
        print("Invalid Operator")


    x = float(input("What's x? "))


    if x == x_answer:
        score += 1 
        print("CORRECT, your score is:", score)
    
    elif x != x_answer:
        score -= 1
        print("INCORRECT, you lost a point! Current score:", score)

Again, just to reiterate the problem: when there's a division question, the answer has to be the entire thing (example: 0.432...) I want the computer to accept 0.43 as the answer and let the score go up if 0.43 is the answer.

So the question is how to compare floating point numbers to a fixed precision? And we don't really need all that other stuff, right? — Kenny Ostrom, Jul 14 '20 at 20:00
Well, I just wanted to know how I could have the computer accept a rounded number as the answer (for division). Currently it accepts the entire answer (ex: 0.32424523). I want the computer to accept it as (0.32). By accept, what I mean is having the score to go up by 1. — Emad, Jul 14 '20 at 20:02

score 1 · Accepted Answer · answered Jul 14 '20 at 20:16

You can try the built in round() function in python around the float value, like so:

elif op == "/":
    print(num1, "/", num2, "= x")
    x_answer = round(float(num1 / num2), 2)

The first value in the round() function gives the value to round and the second tell python to what decimal place. In this example you want to the 2 decimal, so put 2.

Kenny Ostrom · Answer 2 · 2020-07-14T20:43:07.580

# this is a unit test for a comparison function f
def test(f):
    # check the case where it should be rounded down
    expected = 0.432
    correct = 0.43
    wrong = 0.44
    if not f(expected, correct):
        raise ValueError
    if f(expected, wrong):
        raise ValueError

    # check the case where it should be rounded up
    expected = 0.437
    correct = 0.44
    wrong = 0.43
    if not f(expected, correct):
        raise ValueError
    if f(expected, wrong):
        raise ValueError

    # need to accept more precision if it's right
    if not f(expected, expected):
        raise ValueError

    print ('passed')

places = 2

# floating point comparison by delta
def equivalent_delta(x, y):
    delta = 5 * 10 ** - (places+1)
    return abs(x-y) < delta

# comparison using builtin function round
def equivalent_round(x, y):
    return round(x, places) == round(y, places)

# compare their string representation with 2 places
def equivalent_print(x, y):
    format_string = '{{:.{}}}'.format(places)
    return format_string.format(x) == format_string.format(y)

# multiply by 100, convert to integer (with 0.5 for rounding)   
def equivalent_as_int(x, y):
    return int(x * 10**places + 0.5) == int(y * 10**places + 0.5)

test(equivalent_delta)
test(equivalent_round)
test(equivalent_print)
test(equivalent_as_int)

A Python Arithmetic Math Game

2 Answers2