Enter a number in the answer box, click out of the answer box, and press the left arrow to enter a value. Type a number in the answer box, click out of the answer box, and press the right arrow to enter a weight for that value. (use actual percentage, not decimal. The percentage is converted to decimal automatically.) Press space to calculate! Press the down arrow to clear all values. Hold the up arrow to hide the "answer box" if you want to do that for some reason.
I don't know why I made this. For Average atomic mass, the "value" is the mass and the "weight" is the percentage.
