Basic Calculator
Everyday Arithmetic Tool
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Getting the Most Out of a Basic Calculator
A basic calculator handles the four fundamental operations of arithmetic — addition, subtraction, multiplication, and division — along with everyday helpers like percentages, parentheses, and memory storage.
Instead of feeding your keystrokes into a raw code interpreter, this calculator uses a dedicated parser that only understands numbers and the operators on the keypad — nothing more can ever run.
The M+, M-, MR, and MC keys work exactly like a physical desktop calculator, letting you stash a running subtotal while you work through a longer multi-step problem.
Order of Operations (PEMDAS)
Every expression is evaluated using the standard mathematical order of operations: Parentheses first, then Exponents, then Multiplication and Division (left to right), and finally Addition and Subtraction (left to right). For example, 2 + 3 × 4 evaluates to 14, not 20, because multiplication happens before addition.
When a Basic Calculator Is Enough
Most everyday math — splitting a bill, checking a discount, tallying a shopping list, or balancing a checkbook — only needs the four core operations plus percentages. For trigonometry, logarithms, exponents, and roots, step up to our Scientific Calculator.
Key Takeaways
-
No
eval(), ever. Every keystroke is parsed by a dedicated recursive-descent evaluator, so nothing but arithmetic can happen. - Order of operations is always respected. Multiplication and division are evaluated before addition and subtraction.
- Memory keys persist across calculations. Use M+ and M- to build a running subtotal, then MR to recall it at any time.
- History keeps your last several results. Scroll the history panel to review earlier calculations without redoing them.
Frequently Asked Questions
- Click the number and operator keys to build an expression, just like a physical calculator.
- Use
(and)to group parts of an expression. - Press
=to calculate the result. - Your calculation is automatically added to the history list on the right.
Yes. Unlike calculators that rely on JavaScript's eval() function on raw text, this tool parses every keystroke with a purpose-built recursive-descent parser. Only digits, a decimal point, and the operators + − × ÷ % ( ) are ever recognized — there is no way for entered text to execute arbitrary code.
Pressing % immediately after a number converts it to its decimal equivalent by dividing by 100 (so 50% becomes 0.5). Combined with the other keys, this lets you compute expressions like 200+10% to add a 10% surcharge on top of 200.
M+ adds the value currently on the display to memory, M- subtracts it, MR recalls the stored memory value into the current expression, and MC clears the memory back to zero. A small M badge appears above the display whenever memory holds a non-zero value.
Yes. Multiplication and division are always evaluated before addition and subtraction, and anything inside parentheses is evaluated first, exactly as in standard PEMDAS/BODMAS math rules.
The calculator catches these cases safely and shows a clear on-screen error message instead of crashing or silently returning an incorrect number — division by zero and mismatched parentheses are both explicitly guarded against.