There are more stars in the universe than grains of sand on Earth.
Why it is true
It is estimated that there are about 1 sextillion stars in the observable universe, vastly surpassing the grains of sand on our deserts and beaches.
Source: Astronomy
Would you rather be asked first?
This is the reading side of the site, so the answer is in the sentence above — that is the whole point of it. Test yourself works the other way round: the question comes on its own, and the fact and the explanation only appear once you have answered.