# Core Pure - Complex Numbers Flashcards

What are the 6 Number categories?

- Natural Numbers
- Rational Numbers
- Positive and Negative Integers
- Irrational Numbers
- Real Numbers
- Complex Numbers

Which type of numbers are real?

- Natural
- Rational
- Integers
- Irrational

What is a Natural Number?

A positive integer, such as 1, 2, or 3

What is a Rational Number?

A number which can be expressed as a fraction, such as ½, ⅓, or ¼

What is an integer?

A whole-valued positive or negative number, such as 1, -1, 2, -2

What is an irrational number

A number which cannot be expressed as a fraction, such as √2, π, e

What is a complex number?

A number in the form a + ib, where i = √-1 and a and b are real numbers

What is an imaginary number?

a real number multiplied by i, where i = √-1

What is the sign for a real number?

R

What is the sign for a natural number?

N

What is the sign for a rational number?

Q

What is the sign for an integer?

Z

What is the sign for an irrational number?

P

What is 2π radians in degrees?

360°

What is π radians in degrees?

180°