Generate a sheet of random math add/subtraction problems for a pre-school child

mathpractice.py

#!/usr/bin/env python3
import random
import operator

def generate_problem(min_op=1, max_op=9, min_res=0, max_res=10):
    operators = [operator.add, operator.sub]
    while True:
        opa = random.choice(range(min_op, max_op+1))
        opb = random.choice(range(min_op, max_op+1))
        oper = random.choice(operators)
        res = oper(opa, opb)
        if min_res <= res <= max_res:
            opsign = "+" if oper.__name__ == "add" else "-"
            return (opa, opsign, opb)

def generate_problems(num=20):
    random.seed()
    problems = set()
    while len(problems) < num:
        p = generate_problem()
        if p in problems:
            continue
        problems.add(p)
        yield "{:d} {:s} {:d} =".format(*p)

latex_header=r"""
\documentclass[a4paper,12pt,twocolumn]{exam}

\usepackage[czech]{babel}
\usepackage{xltxtra}
\usepackage{hyperref}
\usepackage{fullpage}
\hypersetup{colorlinks=false,hidelinks}
\setromanfont[Scale=.9]{DejaVu Serif}
\setsansfont[Scale=.9]{DejaVu Sans}
\setmonofont[Scale=.85]{DejaVu Sans Mono}


\begin{document}
\pagestyle{empty}
\Huge
"""
latex_item = r"""
\makebox[.35\textwidth]{{$ {} $\enspace\hrulefill}}
\vspace{{1.5em}}
"""
latex_footer = r"""
\end{document}
"""

def latexout(problems):
    print(latex_header)
    for p in problems:
        print(latex_item.format(p))
    print(latex_footer)

def main():
    latexout(generate_problems(22))


if __name__ == '__main__':
    main()