[BlindMath] How to display answers to solution?

[Abdulqadir Ahmad]

Hi,

I can't help it. I'd like my stuffs to look nice.

When I used to write math on paper with pen (back in the days 😊), I 
used to write a double slanted line at the write edge of my answers.

Can I do it in latex? If no, how can I visually separate my answers?

Lastly, do people really use QED (Q.E.D)?

With best wishes,

Abdulqadir Ahmad