# Lesson 15

Changing the Score

• Let’s keep increasing or decreasing an amount by a percentage.

### 15.1: Math Talk: Rewriting Expressions

Express each percent change using an expression that only uses multiplication.

$$x$$ increased by 5%

$$y$$ decreased by 10%

$$z$$ increased by 25%

$$w$$ decreased by 2.5%

Round 1: Your starting score is 50. Roll your number cube 10 times. If you are in group

• A, your score increases by 5% every time you roll a 4, 5, or 6 (and stays the same otherwise).
• B, your score increases by 10% every time you roll a 5 or a 6 (and stays the same otherwise).
• C, your score increases by 20% every time you roll a 6 (and stays the same otherwise). Compute your new score after each roll.
 roll calculation new score 0 1 2 3 4 5 6 7 8 9 10 50

Round 2: Your starting score is the result from Round 1. Roll your number cube 10 times. If you are in group

• A, your score decreases by 5% every time you roll a 6 (and stays the same otherwise).
• B, your score decreases by 10% every time you roll a 5 or a 6 (and stays the same otherwise).
• C, your score decreases by 20% every time you roll a 4, 5, or 6 (and stays the same otherwise). Compute your new score after each roll.
 roll calculation new score 0 1 2 3 4 5 6 7 8 9 10