Daily UI Challenge - Day 4 - Calculator

Day 4 of the Daily UI Challenge - Calculator

Design a calculator. Standard, scientific, or specialty calculator for something such as a mortgage? Is it for a phone, a tablet, a web app?

In the past my boyfriend created an excel sheet with code to calculate their grades. I was inspired by their idea to create a grades calculator app where the user can insert their own courses and score then the grade letter will auto generate. After calculating it will have a popup with the calculations of the grades inserted. I believe this tool would help out a lot of students that want to keep track of their class averages or their test average for a class.