A8. Which of the following expressions has the greatest value for $a=2$ and $b=\frac{1}{2}$?
(A) $a+b$
(B) $a b$
(C) $a-b$
(D) $a: b$
(E) $b: a$
A8. The values of the expressions for $a=2$ and $b=\frac{1}{2}$ are $a+b=2+\frac{1}{2}=2 \frac{1}{2}$, $ab=2 \cdot \frac{1}{2}=1$, $a-b=2-\frac{1}{2}=1 \frac{1}{2}$, $a: b=2: \frac{1}{2}=4$, $b: a=\frac{1}{2}: 2=\frac{1}{4}$. The expression with the greatest value is $a: b$.

## FURTHER PROBLEMS