Part 1
<span>Using rounding or compatible numbers, we estimate the product

to

Therefore, the estimate of the product </span><span>

, using rounding and compatible numbers is about 15.</span>
Part 2
<span>Using rounding or compatible numbers, we estimate the quotient

to

Therefore, the estimate of the quotient </span><span>

, using rounding and compatible numbers is about 9.</span>
Part 3
Given that Mr.
Garcia's class ate

pizzas, Mrs Rizzoli's class ate <span>

pizzas,
and Mrs. Tindal's class ate </span><span>

pizzas.
Using benchmarks, we estimate the
total number of pizzas eaten by all three classes as follows: </span>

,

and <span>

Thus, the </span><span>total number of pizzas eaten by all three classes is given by

Therefore, </span>the <span>total number of pizzas eaten by all three classes is about 11.</span>