Estimates Formulas Derivations

Mental Calculations is a collection of unsuitable for actual use mental exercises designed by the infamous Oblivion. These are meant for the sole purpose of driving one mad with the sheer futility of mental arithmetic.

Estimate the number of grains of sand in the Grand Canyon, Solve for x in the equation 2x+5=11, and Derive the square root of -1

Oblivion's Notes
1. The number of grains of sand in the Grand Canyon is approximately 4.4 billion. Do not attempt to calculate the exact number, as it will drive you mad.
2. The square root of -1 is undefined. Do not attempt to derive it, as it will result in a logical contradiction.