We all have that one calculator app that can do complex calculations, calculate tips at the restaurant, estimate mortgage payments, and find investment returns. Not to mention figuring out how much change you’d receive after purchase. Calculator apps are our all-time saviors!! What if we told you there’s a calculator app that can help you with infrequent but equally important calculations? Like figuring out the quantity of paint for room painting or water tank filling time? Enter Calsy. Calsy is …