A father is buying cheeseburgers for his children. Each cheeseburger costs $3.50. He spends $17.50 on cheeseburgers. How many cheeseburgers did he buy?

Answer 1

if n = the number of cheeseburgers

then

3.50n = 17.50

n = 17.50/3.50

n = 5

Answer 2

Start at $17.50 and start subtracting $3.50 (imagine you pay for each one, one at a time)

$17.50 - $3.50 = $14

$14 -$3.50 = $10.50

$10.50 - $3.50 = $7

$7 - $3.50 = $3.50

$3.50 - $3.50 = $0

The father bought 5cheese burgers

Alternate method

Compute $17.50 divided by $3.50

Division works because division is repeated subtraction