Stretch: Substitute and Evaluate
I can evaluate an expression at a given value and use a formula by substituting numbers.
🧠 The Challenge
substituteevaluateformulaorder of operations
To evaluate, replace each variable with its value and compute. A formula like A = ℓ × w works the same way: substitute the numbers, then calculate.
👀 Worked Example
Evaluate 3x + 2 at x = 4: 3(4) + 2 = 12 + 2 = 14. Use A = ℓ × w with ℓ = 5, w = 3: A = 5 × 3 = 15.
✏️ Your Turn
0 of 3 checks complete
1. Evaluate 2x + 5 when x = 3.
2. Using A = ℓ × w with ℓ = 6 and w = 4, A = ?
3. Evaluate x² when x = 5.
💬 Explain Your Thinking
Show how to evaluate 4n + 1 when n = 6:
"I substitute n = 6, so 4n + 1 = 4 × blank + 1 = blank + 1 = blank."