DS6 wants a calculator for Christmas, for fun around the house - no calculators allowed in school yet. I don't think we're ready for a scientific calculator (or maybe we are, and I just give him my old one, which is a simple TI one). He specifically wants a calculator where he can read the equations in the display screen - not a calculator where you type 22+45, and as soon as you type the 45, the 22 disappears. Any recommendations?