Calculator FAQ: Common Math Questions Answered

To find what percentage X is of Y, use the formula: (X ÷ Y) × 100. For example, 25 is 50% of 50 because (25 ÷ 50) × 100 = 50. To find a percentage of a number, multiply: 30% of 80 = 0.30 × 80 = 24. Use our free Percentage Calculator for instant results.

GPA (Grade Point Average) is calculated by multiplying each course's grade points by its credit hours, summing those products, then dividing by the total credit hours. For example, an A (4.0) in a 3-credit course contributes 12 grade points. Use our free GPA Calculator to calculate your semester or cumulative GPA instantly.

To add fractions, find a common denominator, convert both fractions, then add the numerators. For example, 1/4 + 1/3 = 3/12 + 4/12 = 7/12. Subtraction works the same way. Always simplify the result by dividing numerator and denominator by their GCD. Our free Fraction Calculator handles all operations instantly.

A prime number is a whole number greater than 1 divisible only by 1 and itself. To check, test divisibility by every integer up to the square root of the number. If none divide evenly, it is prime. For large numbers, this is tedious by hand. Use our free Prime Number Checker for instant results.

A scientific calculator handles advanced math beyond basic arithmetic — trigonometry (sin, cos, tan), logarithms, exponents, roots, and factorial. It is essential for high school and university science, engineering, and statistics coursework. Use our free Scientific Calculator online from any device.

Compound interest is calculated as A = P(1 + r/n)^(nt), where P is principal, r is annual rate, n is compounding frequency per year, and t is time in years. Compound interest grows faster than simple interest because you earn interest on your interest. Try our free Compound Interest Calculator.

Number base conversion changes a number from one positional numeral system to another. Decimal (base 10) uses digits 0–9; binary (base 2) uses 0 and 1; hexadecimal (base 16) uses 0–9 and A–F. For example, decimal 255 = binary 11111111 = hex FF. Convert between bases with our free tool.

The order of operations (PEMDAS/BODMAS) determines the sequence in which mathematical operations are performed: Parentheses first, then Exponents, then Multiplication and Division (left to right), then Addition and Subtraction (left to right). Ignoring this order produces incorrect results. Our Scientific Calculator follows these rules automatically.