Questions about the calculator
The keys are on the home page. These answers match how they actually behave.
Does this follow order of operations?
Yes. When you press equals, multiplication and division are done before addition and subtraction. 2 + 3 × 4 is 14, not 20. The smaller line above the digits shows the whole expression so you can see what will be evaluated. There is no bracket key. If a sum needs brackets, do the bracketed part first and let it land on the tape, then continue.
What does the percent key do?
It depends on the operator in front of it. 200 + 10% means 200 plus 10 percent of 200, which is 220. 200 − 10% is 180. 200 × 10% means 200 times 0.1, which is 20. 200 ÷ 10% is 200 divided by 0.1, which is 2,000. With no operator, 50% becomes 0.5. Percent applies to the number immediately before the plus or minus, not to a running total of several additions.
Are sine, cosine, and tangent in degrees or radians?
Degrees. sin(90) is 1 and cos(0) is 1. If a textbook gives radians, convert before you type: degrees = radians × 180 / π. The π key inserts π so you can do that conversion on the tape. Scientific keys act on the number currently displayed.
Is my history saved?
Only for as long as the tab stays open. The tape is not written to disk and not sent anywhere. Clear tape wipes it immediately. A reload also wipes it, including memory.
Can I use the keyboard?
Yes. Type digits, a full stop or comma for the decimal point, and + − * / for the operators. Enter or equals evaluates. Backspace deletes the last digit you typed. Escape or Delete clears. Keyboard input is ignored while you are in a text field on another page, and on this page there is nowhere else to type.
What happens if I divide by zero?
The display shows Error and the expression stops. Press C once to reset. Square root of a negative, 1 divided by 0, and tangent of 90 degrees do the same. Those are not numbers this calculator will invent a value for.
Why did I get a long decimal?
The calculator uses ordinary computer numbers and then rounds to 10 decimal places, stripping leftover zeros. A third of a third will not always print as a neat fraction. Very large and very small results switch to scientific notation. Do not use it for certified engineering tolerances or for money if you need exact decimal rounding rules from a particular accounting standard. For money, check the last digit yourself.
What if I press equals right after an operator?
The number still on the display is used as the missing right-hand side. 5 + = becomes 5 + 5. It is the same habit as a desktop calculator when the next number was never typed.
Do you see what I calculate?
No. There is no account, and the page does not post sums to a server. The privacy notice says the same thing in more detail.