#### Answer

Estimate: $18$
Exact: $20$

#### Work Step by Step

Estimate: Round the numbers to 6 and 3 and multiply.
Exact: Turn numbers into improper fractions: $\frac{25}{4}, \frac{16}{5}$
multiply: $\frac{25}{4}\times\frac{16}{5} = \frac{20}{1}$
Convert to a mixed ( or whole) number: $20$