#### Answer

Estimate: $3$
Exact: $4$

#### Work Step by Step

Estimate: Round the numbers to 3 and 1 and multiply.
Exact: Turn numbers into improper fractions: $\frac{28}{9}, \frac{9}{7}$
multiply: $\frac{28}{9}\times\frac{9}{7} = \frac{28}{7}$
Convert to a mixed (or whole) number: $4$