Check out the customer images. The main function keys (far right column) are very hard to read. They are not painted black as shown in the ad. They are only a slight indentation on an otherwise bright silver pad. Unless you have 20/20 vision, or better, you will be probably constantly confuse the ( - ) for the divide sign, and the (+) sign with the times sign. It is only issue that I have with this product, but it's a big one. Otherwise, it seems to function well. I know that it's a $20 calculator. But, they all are - or less. I would happily have paid $30 or more for a calculator with function keys that I can easily see. But, this is for school, so I had to keep it simple and non-programable. And, if you're in direct light it can be even worse as the light reflects easily off the silver paint, so you need to hold it a little sideways to avoid reflection. Not a smart color scheme.