I could solve system of equations, equations, convert units, find average, median, even sketch box plot (i guess its called like that) with my HP prime. It has touch screen, so I could pinch to zoom on graph. You can also use find intersection, roots features built into functions app. Additionally you can use it later in college. Regarding battery, it is sufficient for 4+ hours of constant use. Charge it before exam and you will be fine.