Foundations

Positive integers used for counting: 1, 2, 3, 4, ...

The set of numbers including positive integers, zero, and negative integers.

A number that can be expressed as a ratio (fraction) of two integers.

A number that cannot be expressed as a fraction, with infinite non-repeating decimal expansion.

The set of all rational and irrational numbers, corresponding to every point on the number line.

The four basic operations: addition, subtraction, multiplication, and division.

A shorthand notation for multiplying a number by itself multiple times.

A number that, when squared, gives the original number.

A natural number greater than 1 that has no positive divisors other than 1 and itself.

GCD (Greatest Common Divisor) is the largest number that divides both numbers. LCM (Least Common Multiple) is the smallest number divisible by both.

A number representing part of a whole divided into equal parts.

A number written using a decimal point to represent fractional parts as powers of ten.

A ratio expressed as a fraction of 100.

A comparison of the relative sizes of two numbers, written as a:b or a/b.

An equation stating that two ratios are equal.

A number system using only two digits: 0 and 1.

A number system using digits 0 through 7.

A number system using 16 symbols: 0-9 and A-F (representing 10-15).

A number combining real and imaginary parts, written as a + bi where i² = -1.