Sorry , idk .........................
Make them both improper fractions.
77/10 - 19/5
Give them common denominators (multiply the second fraction by 2)
77/10 - 38/10
Subtract
39/10 = 3 9/10
Since 32 mil is 1/10 of the US pop, multiply 32 mil by 10 so you get the 10/10 aka the whole US pop. That means it would be 320,000,000. All you do is add a zero to 32 mil since you multiply by 10. 32 mil originally had 6 zeros. After multiplying, you have 7 zeros.