The human brain is located in the upper portion of the head with a volume that could be approximated by a cube 1=20 cm on a side. Brain cells,
consisting of 10% neurons and 90% glia vary in size with dimensions ranging
from a few microns to a metre or so. Taking d=10 microns as a typical
dimension and consider a cell to be a cube with each side having that length,
estimate the number of brain cells in the human brain.​