You can save this page locally (it works well without network connection) and perhaps create a desktop shortcut for it, for use in systems that lack a sufficiently good built-in calculator.
The calculator works much the same way calculators usually do. To calculate the product 9 × 17, just click on the buttons in this order. Keyboard keys do not work.
The E button adds the letter E to the number being written, where it stands for “times ten to the power”, as usual in programming. The ln, lg, and lb buttons compute the natural logarithm, the base 10 logarithm, and the base 2 logarithm, respectively, of the current value. The log button computes a general logarithm klog x when you first enter k, then click on the button, then enter x, and finally click on the button.