-40(1/2 x 45)=

A lot of my students are not comfortable turning fractions into decimals.  For students who want to avoid decimals, look below. With this problem I would have them convert 45 into a fraction by putting a one in as the denominator

Step One-change 45 into a fraction: -40 (1/2x45/1)

Step two: multiply the fractions within the (  )

                 -40 (45/2)

Step 3: Convert -40 into a fraction

               -40/1 (45/2)

Step 4: Simplify  fractions (2 goes into -40, -20 times)

               -20/1 (45/1)

Step 5: Multiply and a - times a + = a negative

             = -900