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Numbers › Real numbers
The real numbers
Every number that has a place on the number line — including the irrationals like π and √2.
The number family
Each ring contains all the ones inside it.
Naturals
Whole numbers
Integers
Rationals
Reals
Naturals
1, 2, 3…
Whole numbers
0, 1, 2, 3…
Integers
…−2, −1, 0, 1, 2…
Rationals
any a/b (b ≠ 0)
Reals
every point on the line
What's outside the reals?
Everything you can write as a decimal — terminating, repeating, or forever-without-pattern — is real. Outside the reals are the imaginary numbers (involving i = √−1) and the complex numbers built from them.