Numbers Secrets
N ⊂ Z ⊂ Q ⊂ R ⊂ C ⊂ H ⊂ O ⊂ S ⊂ T ⊂ ⋯ displaystyle mathbb N subset mathbb Z subset mathbb Q subset mathbb R subset mathbb C subset mathbb H subset mathbb O subset mathbb S subset mathbb T subset cdots The earliest recognised use of irrational numbers was inside the Indian Sulba Sutras composed amongst 800 and 500 BC.[23][improv