Precedence you can inspect
Start with (2+3)*sqrt(16)+2^3. Parentheses produce 5, the square root is 4 and the power is 8, so the result is 28. Correcting the first 3 to 4 gives 32. Powers group from the right: 2^3^2 means 2^(3^2)=512. A leading minus applies after a power, so -2^2=-4 but (-2)^2=4. Multiplication and division proceed left to right. Implicit multiplication has ordinary multiplication priority: 1/2 pi means (1/2)*pi; write 1/(2 pi) for the other meaning.
Angles and percentages are conventions
Select DEG before sin(30) to obtain approximately 0.5; choose RAD before sin(pi/2) to obtain 1. Inverse trig returns the selected unit too: asin(0.5) in DEG is approximately 30. The percent operator divides by 100, so 200+10%=200.1. For an increase use 200*(1+10%)=220. The context panel and copied summary preserve these rules. Switching angle mode previews a new interpretation but does not rewrite previous history.
Recall and correct with the original settings
Calculate sin(30) in DEG, then calculate sin(pi/2) in RAD. Recall the first history entry: DEG returns, with a visible announcement and the original expression. Edit it to sin(90) and calculate again to get 1. Clear entry leaves other work intact; clear history leaves the draft intact. Reset all or reload clears the temporary session. Nothing is shared through a URL or stored on the device.
Recognize numerical and notation limits
Use a decimal point and no grouping punctuation. Functions require parentheses: ln(e)=1 and cbrt(-8)=-2. The evaluator deliberately does not infer rational exponents in (-8)^(1/3), even though its real cube root exists; use cbrt(-8). sqrt(-1), ln(0), division by zero and recognized tangent singularities need a different real expression. Results are approximate; very small nonzero underflow is reported instead of shown as exact zero. Keep expressions within 1024 characters, 512 tokens and 64 nested levels.