Methods of Math Teaching and Learning

  The following problem is a type of problem my preservice teachers encounter on the Praxis II Multiple Mathematics assessment:  If the price of a computer, including a 9% tax, is $3,545.00, what is the cost of the computer before the tax is added? Traditionally, students are asked to find the cost of an item after adding tax to the original cost. Moreover, students are asked to find the total cost of an item after applying some sort of discount. The above problem is like a reverse operation or is it.  Let's review how to compute sale tax and the cost of something after adding the sale tax. Let's say a computer costs $1575 without the tax included. There is an 8% tax to add to the cost of the computer. $1575 X .08= $126. Then, add the $126 to the cost of the $1575 + $126=$1701. The computer will cost $1701. This does not include the warranty or service plan.  The math is straightforward computation, and the situation is real world. What Praxis wants to know is if you can calcul