This generates a game where there is an algebraic expression whose operations are hidden. It's from this Reddit post: https://redd.it/8r0a66

number_game.py

import random

def generate_game(largest_number, length, difficulty):
    """Produce an example of the number game.
    - largest_number is the largest possible number that can appear
    - length is how many numbers will appear in the problem
    - difficulty = 0,1,2. 0 has just addition/subtraction, 1 introduces multiplication, 2 has +,-,*,/
    """
    # Set difficulty
    operations = ['+', '-']
    if difficulty > 0:
        operations.append('*')
    if difficulty > 1:
        operations.append('/')
    
    # Add numbers and operations
    game = [str(random.randint(0,largest_number))]
    for i in range(length-1):
        game.append(random.choice(operations))
        game.append(str(random.randint(1,largest_number)))
    
    # Make hidden game. Remove the operations.
    hidden_game = ""
    for i in range(len(game)):
        if i % 2 == 0:
            hidden_game += str(game[i])
        else:
            hidden_game += "_"
    hidden_game += " = " + str(eval(''.join(game)))
    print hidden_game
    
    x = raw_input("Click to see a solution.")
    print ''.join(game) + " = " + str(eval(''.join(game)))
    print '----------'
    return None

# Play!
s = int(raw_input("What's the largest number you want to appear? (Enter a whole number larger than 0)"))
l = int(raw_input("How many numbers do you want to appear? (Enter 1,2, ..., 10)"))
d = int(raw_input("What difficulty do you want? 0 = + and - only, 1 contains multiplication, 2 contains all operations."))
for i in range(int(raw_input("How many games do you want to play? (Enter 1,2, ..., 10)"))):
    generate_game(s, l, d)
print "Thank you for playing!"

Fixed the order of operations.

I'm using eval() to find the solution now. This avoids having to hardcode the order of operations.