# How many $$4\frac{1}{2} \text { gallons }$$ cans worth of gas would you need to pour into an empty 19 gallon tank to fill it exactly halfway?

$$2$$

Explanation

calculate how many gallons of gas are needed to fill a 19 gallon tank halfway:  $$19 \div 2 = 9\frac{1}{2} \text { gallons }$$ .
, calculate how many $$4\frac{1}{2} \text { gallon }$$ cans are needed to reach $$9\frac{1}{2} \text { gallons }$$
$$9\frac{1}{2} \div 4\frac{1}{2} = \frac{{18}}{2} \div \frac{9}{2} = \frac{{18}}{2} \times \frac{2}{9} = \frac{{18}}{9} = 2$$