Solution: Page 245 (Expressions)

Figure it Out - Set 1

1. You start from Floor +2 and press –3 in the lift. Where will you reach? Write an expression.

• Start: $+2$
• Movement: $-3$ (Down 3)
• Calculation: From $+2$, go down 1 to $+1$, down another to $0$, down another to $-1$.
• Expression: $(+2) + (-3) = -1$
• Answer: Toy Store (Floor -1).

2. Evaluate these expressions:

• a. (+1) + (+4) = $+5$
• b. (+4) + (+1) = $+5$
• c. (+4) + (-3) = $+1$ (Start at 4, go down 3)
• d. (-1) + (+2) = $+1$ (Start at -1, go up 2: -1 $\to$ 0 $\to$ 1)
• e. (-1) + (+1) = $0$ (Inverse property)
• f. 0 + (+2) = $+2$
• g. 0 + (-2) = $-2$

Figure it Out - Set 2

3. Find movements required to reach Floor –5.

Formula: $\text{Start} + \text{Movement} = \text{Target (-5)}$

• Example from text: Start at $+2$. Movement is $-7$. $(+2) + (-7) = -5$.
• Start at +1: $1 + (-6) = -5$ (Move down 6).
• Start at -2: $-2 + (-3) = -5$ (Move down 3).
• Start at 0: $0 + (-5) = -5$ (Move down 5).