Question

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?

Answer 1

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).