How to Solve Exponents and Powers — Step by Step Guide
Laws of exponents, scientific notation, and simplification. This guide covers Class 7 to 8.
Step-by-Step Method
- 1
Understand the notation: a^n means a multiplied by itself n times.
- 2
Key laws: a^m × a^n = a^(m+n), a^m ÷ a^n = a^(m-n), (a^m)^n = a^(mn).
- 3
Special cases: a^0 = 1 (for a ≠ 0), a^(-n) = 1/a^n.
- 4
To write in standard form (scientific notation): express as a number between 1 and 10 multiplied by a power of 10.
- 5
When simplifying, apply the laws step by step and combine like bases.
Worked Example
Problem: Simplify 2³ × 2⁵ ÷ 2⁴
Solution: 2³ × 2⁵ = 2⁸. 2⁸ ÷ 2⁴ = 2⁴ = 16.
Common Mistakes to Avoid
- ✗
Multiplying the base along with the exponent: 2³ × 2⁴ ≠ 4⁷, it equals 2⁷.
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Confusing (ab)^n with a^n × b — it should be a^n × b^n.
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Forgetting that a^0 = 1, not 0.
- ✗
Incorrect handling of negative exponents.
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Frequently Asked Questions
- How do I solve Exponents and Powers problems?
- Understand the notation: a^n means a multiplied by itself n times. Key laws: a^m × a^n = a^(m+n), a^m ÷ a^n = a^(m-n), (a^m)^n = a^(mn).
- What are common mistakes in Exponents and Powers?
- Multiplying the base along with the exponent: 2³ × 2⁴ ≠ 4⁷, it equals 2⁷. Confusing (ab)^n with a^n × b — it should be a^n × b^n.
- Which class covers Exponents and Powers?
- Exponents and Powers is typically taught in Class 7, 8. SparkEd has free practice for all these grades.
- Where can I practise Exponents and Powers for free?
- SparkEd offers free chapter-wise practice for Exponents and Powers aligned to CBSE, ICSE, and IB curricula. Visit sparkedmaths.com to start.
SparkEd Maths — sparked.coms@gmail.com — www.sparkedmaths.com