So I did 24- 6 (pack of pens) = 18 (what he used for calculators) and then did 18/2 because he bought two calculators. He paid 9 dollars for each calculator
Kai bought two packs of pens = 12 dollars. 45-12=33, how much he used for the calculators. He bought three calculators so I did 33/3=11. He used 11 dollars for each calculator.