Learn how rounding numbers works for decimals, sums, and significant figures. Get the rules and examples for various quantities.
Mathematics
Learn about the Pythagorean theorem in geometry. Get its definition, formula, and worked example math problems.
Pythagorean Theorem – Definition, Formula, Problems
Learn about the number zero. Get the definition and interesting zero facts and learn about its history and role in math.
Number Zero Definition and Facts
Learn how to calculate a tip without a calculator easily in your head. See examples and know how much to tip for different services.
How to Calculate a Tip Without a Calculator
Learn what an exact number is in chemistry, physics, and math. Get the definition and examples of exact numbers.
What Is an Exact Number? Definition and Examples
Learn how to convert degrees to radians and back again. This is a key angle conversion in geometry and trig.
How to Convert Degrees to Radians – Angle Conversion
Learn what the absolute value or modulus of a number is in math. Get examples and see how to solve absolute value equations.
What Is Absolute Value? Definition and Examples
Learn what a prime number is and see how to tell if a number is prime. Get a list of primes under 100 and 1000.
What Is a Prime Number? How to Tell If a ...
Learn what a real number is in math. Get examples of numbers that are real versus those that are imaginary.