There are approximately 7.5×10^18 grains of sand on earth. There are approximately 7×10^27 atoms in a average human body. Are there more grains of sand on earth or atoms in a average human body? How do you know?
There are more atoms in average human body than grains of sand on Earth. We can know it because we can see that atoms' number (7 * 10^27) is being multiplied by much greater number (with 9 zeros more) than grain's number (7.5 * 10^18).
