Bishnu Dada! Why you wasting money. As DJ r told, go to play store and purchase free of cost
Edited: @Bishnu15 Dada I bought this @₹150. Still it good condition
Exactly. Or why would Bishnu dada ask for a calculator? My advice is to go for a simple Citizen or Orpat calculator. Since your work is mostly tallying of marks, the calculator can be bought for within ₹300. It may have an old-school feel but other options are there as well. For instance the Casio SL-460L that I had many years ago. It is smaller than the palm of the hand.
I am using Casio MJ-120D. It's a basic calculator. 150 steps check, 12 digit, Tax Keys, Two way power.. Price around 400. Casio is the best calculator manufacturer.
Yes. Better than citizen. I had a citizen, lasted only 1 year. Orpat also makes so many products like clock, landline, electric kettle etc.. Good company.
Blindly go for Casio. I bought a Casio 350ms scientific calculator in 2013 that time i was studying first year college and i have it still now working like a charm. In 991ms we can do some matrix calculations.
But clarify with your school/college whether you can use ES OR MS scientific calculator. In some Universities ES model is banned in exams.