This calculator evaluates operations in the order you press them — left to right — rather than following mathematical order of operations (PEMDAS/BODMAS). That's how physical calculators and most simple on-screen calculators work: press 10 + 5 × 2 = and you'll get 30 (it does 10 + 5 first, then × 2), not 20.
If you need an expression evaluated using proper order of operations — where multiplication and division happen before addition and subtraction — you'll want a scientific calculator instead, which typically lets you type the whole expression before evaluating it.
Most likely an order-of-operations mismatch. This calculator computes step by step in the order you press buttons, not by evaluating a full expression. Try entering the same numbers into your phone's calculator app to compare — many follow the same left-to-right logic.
Yes. Number keys, +, −, *, /, Enter (or =), Backspace, and Escape (clear) all work directly.
It converts the current number on screen to its decimal percentage equivalent (e.g. 50 becomes 0.5), matching how most basic calculators handle the percent key.
Yes — use the decimal point button for fractional values, and +/− to flip the sign of the current number.
The display shows "Error," since division by zero is mathematically undefined. Press AC to clear and start over.