In an old story, a man puts 2 grains of rice on the first space of a chess board. He puts 4 grains on the second space, 8 grains on the third space, and so on. Write and evaluate an expression with exponents to find how many grains of rice the man puts on the tenth space.

we know that
a1----------> grains of rice in the first square
a1=2
n------------> space ubication
the expressions  is
 an=a1^n----------> an=2^n

for the the tenth space  n=10
an=2^10---------> an=1024 grains of rice

the answer is
1024 grains of rice