Tessa had $35. She bought a book for $7 and a magazine for $5. Which expression correctly shows the total money Tessa has left?
a. $35 − (−$7) + (−$5)
b. $35 + (−$7) − (−$5)
c. $35 + (−$7) + (−$5)
d. $35 − (−$7) − (−$5)
@Opcode

Question

Tessa had $35. She bought a book for $7 and a magazine for $5. Which expression correctly shows the total money Tessa has left? 
a. $35 − (−$7) + (−$5)
b. $35 + (−$7) − (−$5)
c. $35 + (−$7) + (−$5)
d. $35 − (−$7) − (−$5)
@Opcode

anonymous · Answer

In both cases money is being taken away from her total amount. A negative negative is a positive, so you don't want any expression with a negative negative. This eliminates A, B, and D, leaving only C. In this expression, both times money is being taken away, making it correct.