Do you have Number Sense?

What is 34 + 57?
How long does it take you to answer that?
5 seconds? 10 seconds? Or more.. ?

I used to take more than 10 seconds if someone threw even a simple mathematical calculation at me.
Because I could not visualize. I just could not see the numbers in my head.
This became a major problem when I started my preparation for GRE.

This struggle with numbers motivated me to create a small interactive site (not mobile friendly, Sorry!) that would help me get friendly with numbers.
Forgive me for the bugs and please do let me know your feedback so I could make the improvements.
So here is NumberSense, the result of my meagre software development knowledge.
I hope this would help many like me.