If you are going to calculate, do it in style! Greater Calculator is the most customizable calculator around. Probably. It allows you to rearrange all of the buttons, so you can create a layout that works for you. Just drop one button on top of another to swap, or drop that button into an empty space. Change the color of any button by dragging the color swatches from the top of the screen onto your target. Mix your own colors by tapping a swatch and changing its red, green, and blue values. The three color swatches give you a palette to work with, so you don't have to remix your colors constantly.
Since this calculator is pretty standard, we've included a history to make complex calculations easier. A tap of the "=" sign will store the answer in the scrollable history, and tapping a history value will pop it right back into the display.
A few more notes: Double-tapping the "clear" button will clear the entire input value. Answers will always clear with one tap. Values will be shown with up to 15 sigfigs, and must be less than 10^16. Numbers smaller than 10^-15 will appear as zero. More sigfigs might be stored than are shown, so don't be surprised if your tiny fractional values behave a little unexpectedly.
Happy custom calculating!