Why does 12+8×3 return 36 instead of 60?
Multiplication precedes addition: first 8*3=24, then 12+24=36. To add 12 and 8 first, calculate 12+8, note 20, clear the display, and calculate 20*3. The current interface has no parentheses keys.
Calculator
Do quick calculations right in your browser.
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How to use the calculator
- Build an expression with the number keys and +, −, ×, or ÷. The display is read-only: direct typing, pasting, parentheses keys, and a percentage key are not available. Use a period for decimals.
- Check the whole expression before selecting =. Multiplication and division precede addition and subtraction; operations with equal precedence run left to right. Do not assume evaluation follows the order in which you clicked the keys.
- Read the result below the display. = does not replace the expression with the answer; pressing more keys continues the previous expression. Use Clear to restart, since there is no last-digit deletion, memory, or history.
Check a total without relying on click order
If you need to add two quantities before multiplying them, calculate that subtotal separately. This interface has no way to enter parentheses, so an intended grouping needs separate calculations.
12+8*3 = 36; 12+8 = 20, then 20*3 = 60
In the first expression, 8*3 is evaluated before the addition. To obtain 60, check the first answer of 20, select Clear, and build 20*3. The answer is not automatically carried into the next calculation.
Tasks for the four arithmetic operations
- Check material quantities: 6*4+2 returns 26 for six packs of four units and two loose units. You must check units and descriptions yourself; the tool only calculates numbers.
- Divide a quantity equally: 84/7 returns 12. This does not check whether splitting whole objects is practical or round an answer to a number of people.
- Use Percentage Calculator when you need to interpret increases, discounts, and their bases. The basic calculator does not have an automatic percentage operation.
Precedence, precision, and display errors
- A period is the decimal separator. The expression 1.5+2.25 returns 3.75; do not use a decimal comma. There is no decimal-place setting or configurable currency rounding.
- An unfinished expression such as 12+, or a number with two periods such as 1..5, displays an invalid-expression message. Division by zero produces a non-finite result and shows an error instead of a usable value.
- Results use JavaScript numbers: 0.1+0.2 can appear as 0.30000000000000004. This comes from binary representation; the display does not apply cent correction or exact decimal arithmetic.
- There are no scientific functions, unit conversion, parentheses keys, or % key. Evaluation uses the whole expression, not a subtotal after each operator. Use separate steps for a grouping you cannot enter.
- This tool supports basic arithmetic checks and does not replace financial, tax, or professional calculations. It does not account for interest rules, taxes, contracts, engineering tolerances, or rounding policies required for your work.
Frequently asked questions
Can I paste an expression or use percentages?
No. The display is read-only and input comes from the available keys, without % or parentheses. For discounts and increases, open Percentage Calculator and choose the operation that matches your question.
Why do I see a long decimal result?
Some decimal fractions have no exact binary representation in the numbers used by the browser. The display has no precision or rounding setting. If you need exact cents or a professional calculation rule, use the appropriate procedure.
How do I continue from the answer?
The answer appears separately and = keeps the original expression. Note the answer, select Clear, and build a new expression with that value. The interface has no memory, history, or button to delete just the last key.