8th grade · Math · Unit 13 of 19
Exponent Rules
Add, subtract, multiply exponents
What your child practices
Properties of integer exponents: multiplying and dividing powers with the same base, a power of a power, zero exponents and negative exponents.
New York State Learning Standards learning standard: NY-8.EE.1 · applying the properties of integer exponents to write equivalent expressions
How we explain it
Children can open this short lesson before they practice.
- Multiply powers with the same base: add the exponents.
- Divide: subtract the exponents. Power of a power: multiply them.
- a⁰ = 1, and a⁻ⁿ = 1/aⁿ.
Example: Simplify 2³ × 2⁴. Same base, so add: 3 + 4 = 7. Answer: 2⁷
Exponent Rules in New York
In the New York State Learning Standards, this is unit 13 of 19 in 8th grade Math, after Congruent Shapes and before Systems of Equations.
Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.
Sample questions
A taste of this unit. In the app, questions change every time and get easier or harder to match your child.
Question 1
What is 4⁻¹?
- 1/4
- −1/4
- −4
- 4
1/4
Hint: A negative exponent means one over: 4⁻¹ = 1/4¹ = 1/4.
Question 2
Simplify (6⁴)⁴.
- 6¹⁷
- 24⁴
- 6¹⁶
- 6⁸
6¹⁶
Hint: A power of a power: multiply the exponents.
Question 3
Simplify 6⁵ ÷ 6².
- 6³
- 6⁷
- 6¹⁰
- 1³
6³
Hint: When you divide powers with the same base, subtract the exponents.
Question 4
Simplify 2³ × 2⁹.
- 2¹²
- 2²⁷
- 2⁶
- 4¹²
2¹²
Hint: When you multiply powers with the same base, add the exponents.
Question 5
What is the value of 3² × 3⁻¹?
- 9
- 27
- 1
- 3
3
Hint: Add the exponents: 2 + (-1) = 1. 3¹ = 3.
Question 6
What is 10⁻²?
- −1/100
- −100
- 100
- 1/100
1/100
Hint: A negative exponent means one over: 10⁻² = 1/10² = 1/100.