HI Tapas, Liked your app, Coincidentally, recently, I too had put in a very similar effort for my son's maths (grade 3) classes. I did it in pure html, js and css, using all the latest JS capabilities (classes, reduce, etc). I too have woven a platform whereby we can just plugin new type of problems without impacting the base framework. I was anyway planning to move it to react+node for my hands-on. Would love to demo you my effort and explore the opportunity of collaboration. I haven't deployed in any cloud env for global access though.