conversations.from: human
conversations.value: Erika is saving for a new laptop. The laptop she wants costs $600. The sales assistant told her that if she traded in her old laptop, the price of the new one would be reduced by $200. She thinks this is a good deal and agrees to do it. She already has some savings in her purse, and has also been paid $150 this week for her part-time job. Her mom agrees to give her $80 to help her. If Erika now only needs an extra $50 to buy the laptop, how much money does she have in her purse?
  Give me a solution to this problem
conversations.from: assistant
conversations.value: Selling the old laptop reduced the cost of the new laptop to $600 – $200 = $400 dollars.
  We know she doesn't have all the money yet, so she actually has $400 – $50 = $350 dollars.
  Some of this money came from her mom, so the money she had herself was $350 – $80 = $270.
  Subtracting her part-time wages shows that she had $270 – $150 = $120 in her purse.