PEAZIT Aha card
Go straight to resources ↓A letter holds a value
A variable represents a value. In one substitution, replace every occurrence of the same letter with the same number.
| x | 2 × x + 1 | Result |
|---|---|---|
| 1 | 2 × 1 + 1 | 3 |
| 3 | 2 × 3 + 1 | 7 |
| 5 | 2 × 5 + 1 | 11 |
One worked example
- 3a + a; a = 2Both occurrences of a represent 2.
- 3 × 2 + 23a means multiplication.
- 6 + 2 = 8Evaluate the numerical expression.
Watch out: 2x + 1 alone is an expression, not an equation. An equation adds a condition such as 2x + 1 = 9.
Goal, prerequisites and card origin
What you will learn: Substitute a value into an expression.
What you need first: Addition and multiplication.
An original PEAZIT working card. Independent expert review and effectiveness testing have not yet taken place. · v1
Show connections
A variable represents a value. In one substitution, replace every occurrence of the same letter with the same number.