THAC0 = 21 - level - hit bonus | 156 (22.9%) | |

Recreation: To Hit Armour Class 0 score for a warrior in *Advanced Dungeons & Dragons*, 2nd Edition. |

*d/dx* ln(*x*) = 1/*x* | 94 (13.8%) | |

Calculus: The derivative of the natural logarithm function is an hyperbola. |

*x*^{n} + *y*^{n} ≠ *z*^{n}, for *n* > 2 | 70 (10.3%) | |

Number theory: Fermat's Last Theorem. |

sin^{2}*θ* + cos^{2}*θ* = 1 | 54 (7.9%) | |

Trigonometry: One of the most fundamental identities. |

*E* = *mc*^{2} | 40 (5.9%) | |

Special relativity: Einstein's famous mass-energy equation. |

*N* = *R*_{*} f_{p} n_{e} f_{l} f_{i} f_{c} L | 37 (5.4%) | |

Astrobiology: The Drake equation. |

*e*^{iπ} + 1 = 0 | 34 (5.0%) | |

Complex analysis: Euler's identity. |

BMI = w/h^{2} | 27 (4.0%) | |

Health: The formula to calculate Body Mass Index. |

1 + 1 = 2 | 23 (3.4%) | |

Arithmetic: A simple addition. |

s->c_str()[s->size()] == '\0' | 22 (3.2%) | |

Computer science: The element of a C-style C++ string at index equal to the string length is a null character. |

2H_{2} + O_{2} → 2H_{2}O | 22 (3.2%) | |

Chemistry: Hydrogen and oxygen make water by combustion. |

**H***Ψ* = *ih/2π d/dt Ψ* | 22 (3.2%) | |

Quantum mechanics: The Schrödinger wave equation. |

*E*_{ik} = 8*πG*/*c*^{4} *t*_{ik} | 14 (2.1%) | |

General relativity: Einstein's field equation. |

*c* = *fλ* | 12 (1.8%) | |

Wave motion: Speed of light is the frequency multiplied by the wavelength. |

∇^{2}Φ = 0 | 11 (1.6%) | |

Differential equations: Laplace's equation. |

*a*^{2} = *b*^{2} + *c*^{2} | 11 (1.6%) | |

Geometry: Pythagoras' theorem for right angled triangles. |

Tr_{{F/Q}} = ∑^{n}_{i=1} *σ*_{i}(*f*) | 10 (1.5%) | |

Algebra: Trace of an element in a number field as an extension of the rationals. |

∫*E*.*d***A** = *q*/*ε* | 10 (1.5%) | |

Electromagnetism: Gauss' law. |

*F** = **ma* | 7 (1.0%) | |

Dynamics: Newton's Second Law |

*B* = *P*(1 + *r*/*n*)^{nt} | 6 (0.9%) | |

Economics: Compound interest formula. |