I have been using this on a home desk environment under an bright office light. I have found it always hard to read the background as it seems very dark. Also I've learned you have to really "hit" the buttons on and watch the screen to make sure they get entered correctly. This is because it's easy for it to not "catch" the numbers you've entered and tends to miss some of them otherwise. I would try to find a product that is higher quality and avoid this one.
Purchased several calculator and no of them worked as well as this one. The buttons are "smooth" and do not malfunction as you try to press them like others. We purchased 2 more since this first purchase.