Question

The mass of a grain of sand is about 10^-3 gram. About how many grains of sand are in a 10kg bag of sand?

Answer 1

10000000

Divide the mass of the bag by the mass of sand. First you need to convert kg to g

Answer 2

The mass of a grain of sand is about 10 to the -3 power gram.
About how many grains of sand are in the bag of sand

Answer

10 kg* (1000 g/ 1 kg)* (1 grain of sand/ 10^(-3) g)= 10^7 grains of sand.
(Note that the units cancel out so you get the answer)
The final answer is 10^7 grains of sand.
Hope this helps~