To keep this simple, I am going to take out the million part of the equation. If 32=1/10 of the US population, then 32x10=the US population. For your answer, 32x10=310.
But don't forget that I took out the million part, so, the US has 310 million people.
To include the 0s, just add 1 0:
32,000,000x10=320,000,000