Django - Arithmetic Operator

Example:

urls.py
    path('arithmetic/', views.arithmetic)

views.py
    def arithmetic(request):
        c=''
        try:
            if request.method=="post":
                n1=eval(request.POST.get('num1'))
                n2=eval(request.POST.get('num1'))
                opr=request.POST.get('opr')
                if opr == '+':
                    c=n1+n2
                elif opr == '-':
                    c=n1-n2
                elif opr == '/':
                    c=n1/n2
                elif opr == '*':
                    c=n1*n2
        except:
            c='Invalid Operation'
        return render(request, 'arithmetic.html', {'c':c})

arithmetic.html
    <form method="post">
        {% csrf_token %}
        <p>Value 1 <input type="text" name="num1">
        <select name="opr">
            <option value="">Select Operator</option>
            <option value="+">+</option>
            <option value="-">-</option>
            <option value="/">/</option>
            <option value="*">*</option>
        </select>
        <p>Value 2 <input type="text" name="num2">
        <button>Submit</button>
        <p>Output: {{c}}</p>
    </form>