1. **State the problem:** You are rooting for the Warriors in a 10-game series against the Lakers. 2. **Given information:** - If the Warriors win a game, you gain 100. - If the Lakers win a game, you lose 90. - Warriors win 4 out of 10 games. 3. **Find:** How much did you gain or lose after 10 games? 4. **Calculate the number of games the Lakers won:** Since there are 10 games total and Warriors won 4, Lakers won $10 - 4 = 6$ games. 5. **Calculate total gain from Warriors' wins:** $$4 \times 100 = 400$$ 6. **Calculate total loss from Lakers' wins:** $$6 \times (-90) = -540$$ 7. **Calculate net gain/loss:** $$400 + (-540) = -140$$ 8. **Interpretation:** You lost 140 by rooting for the Warriors in this series. **Final answer:** You lost 140.