Numbers (for linguistic learners)
Nadia Mulvihillにより
1. Imaginary Numbers (negative under a square root, zero in the denominator)
2. Real Numbers (all numbers except imaginary)
2.1. Irrational (square root that is not a perfect square, pi, a decimal that never ends AND does not repeat)
2.2. Rational (all real numbers except irrational)
2.2.1. Integers (only whole numbers, can be negative or positive)