Expressions and Exponents
Aligned to 6.EE.A.1 — Common Core State Standards for Mathematics.
What this lesson teaches
An exponent is a short way to show repeated multiplication, so 2 to the third power means 2 times 2 times 2. In algebra, a letter called a variable can stand for an unknown number, and you can write and evaluate expressions using these tools.
Worked examples
Example 1
Evaluate 2 to the 3rd power: 2 times 2 times 2 equals 8. Then evaluate 3x when x is 4: 3 times 4 equals 12.
Example 2
Evaluate 5² + 3²: 25 + 9 = 34. Note that is not (5+3)² = 64 — you square each number first.
Example 3
Evaluate x³ when x = 2: 2 × 2 × 2 = 8. An exponent of 3 means three factors, not 'times 3'.
Practice questions
- What does 5 squared equal?
- Write 'four more than a number' as an expression.
- Evaluate 2x + 1 when x is 6.
Watch the lesson
Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.
▶ Watch this lessonEn español
Expresiones y Exponentes
Un exponente es una forma abreviada de mostrar una multiplicación repetida, así que 2 a la tercera potencia significa 2 por 2 por 2. En álgebra, una letra llamada variable puede representar un número desconocido, y puedes escribir y evaluar expresiones usando estas herramientas.
Ejemplo 1: Evalúa 2 a la 3ª potencia: 2 por 2 por 2 es igual a 8. Luego evalúa 3x cuando x es 4: 3 por 4 es igual a 12.
Ejemplo 2: Evalúa 5² + 3²: 25 + 9 = 34. Ojo: no es (5+3)² = 64 — primero elevas cada número al cuadrado.
Ejemplo 3: Evalúa x³ cuando x = 2: 2 × 2 × 2 = 8. Un exponente 3 significa tres factores, no 'por 3'.
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