## Algebra 1: Common Core (15th Edition)

$1/18$
We first multiply 5/9 by 10/10 and 5/10 by 9/9 (this is legal because 9/9 and 10/10 equal 1) to create a common denominator, which allows us to subtract the two expressions. Thus, we obtain: $\frac{50}{90}$-$\frac{45}{90}$=$\frac{5}{90}$=$\frac{1}{18}$