๐ Built around learning practices commonly promoted by leading university teaching centers.
How this basic calculator works
This calculator handles the four core operations โ addition, subtraction, multiplication, and division โ following standard order of operations, so multiplication and division are applied before addition and subtraction in any expression that mixes them. It's built for quick, everyday math: splitting a bill, checking a total at the store, or working through homework problems that don't need trig or exponents.
Calculating a percentage without a % key
Even without a dedicated percent button, percentages are simple division and multiplication. To find 20% of 85, multiply 85 by 0.20 (move the decimal two places left from 20%). To find what percent one number is of another โ say, what percent 34 is of 200 โ divide 34 by 200 and multiply by 100. This same method covers tips, discounts, and sales tax without needing a separate percentage tool.
Common everyday calculations
Tip: multiply the bill by 0.15, 0.18, or 0.20 depending on the percentage you want to leave, then add that to the original bill.
Sales tax: multiply the price by your local tax rate as a decimal (7.5% tax = multiply by 0.075), then add that to the price.
Discount: multiply the original price by the discount rate, then subtract that amount from the original price โ a 25%-off item multiplies the price by 0.25 to find the amount taken off.
Frequently asked questions
Why did my answer come out negative when I expected a positive number?
Check the order you subtracted in โ 10 โ 15 gives โ5, while 15 โ 10 gives 5. It's an easy digit-order slip when you're moving fast, especially when copying numbers from a receipt or worksheet.
Does this calculator save my previous calculation?
No โ each new calculation starts fresh once you clear or begin typing a new expression, so if you need a result for a later step, write it down or use the on-screen result before moving to your next calculation.
I need trig functions or exponents โ where are those?
Head over to our Scientific Calculator โ it has everything here plus trigonometry, logarithms, and scientific notation for more advanced math.
