🚀 Middle School
| IB • Mathematics

Indices

Index laws, zero and negative indices.

1 Lesson 1 MCQ 1 Mnemonic
+30
XP
Available to earn
1
Lesson

Indices — Lesson

1) Hook — The Cricket Power Play of Numbers!

Imagine you are at a cricket match watching your favourite player hit sixes one after another. Now, think of the number of runs scored if the player hits 2 sixes in a row, then 3 sixes, then 4 sixes. Instead of adding 6 + 6 + 6 + ..., what if we could multiply powers of 6 to quickly find the total runs? This is where indices or exponents come in handy — they help us express repeated multiplication in a neat way! Just like a cricket power play boosts the game, indices boost our math skills.

2) Core Concepts — Understanding Indices

An index (plural: indices) or exponent tells us how many times a number, called the base, is multiplied by itself.

Expression Meaning Example
34 3 multiplied by itself 4 times 3 × 3 × 3 × 3 = 81
53 5 multiplied by itself 3 times 5 × 5 × 5 = 125

Here, 3 and 5 are the bases, and 4 and 3 are the indices or exponents.

3) Key Formulas/Rules — The Power Play Rules of Indices

Rule 1: Multiplying powers with the same base

am × an = am+n

Rule 2: Dividing powers with the same base

am ÷ an = am−n (where m > n)

Rule 3: Power of a power

(am)n = am×n

Rule 4: Power of a product

(ab)n = an × bn

Rule 5: Any number to the power zero

a0 = 1 (where a ≠ 0)

4) Did You Know? — Bollywood’s Exponential Growth!

The Indian film industry, Bollywood, produces around 1000 films every year! Imagine if the number of films produced doubled every year (like powers of 2). In just 5 years, that would be 1000 × 25 = 1000 × 32 = 32,000 films! While this is just a fun example, it shows how quickly things can grow exponentially — just like powers in math.

5) Exam Tips — Score Like a Pro!

  • Always write the base and exponent clearly. Don’t confuse 34 (3 to the power 4) with 34 (thirty-four).
  • Remember the zero power rule: Any non-zero number raised to 0 is 1. For example, 70 = 1.
  • When multiplying powers with the same base, add the indices. For example, 23 × 24 = 27.
  • Watch out for negative exponents in higher classes, but for now focus on positive integers.
  • Board exam pattern: Expect questions like simplifying expressions using index laws, evaluating powers, and word problems involving repeated multiplication.
  • Common mistake: Mixing up multiplication and addition of indices. Remember, indices add only when bases are the same and you multiply the powers.
2
MCQ Practice

Indices — Mcq

3
Memory Trick

Indices — Mnemonic

Mnemonic 1: "BOMB Rule for Indices" 💣

Remember the basic operations with indices using the word BOMB:

  • B - Base same, add powers: am × an = am+n
  • O - One power rule: a1 = a
  • M - Minus power means reciprocal: a-n = 1/an
  • B - Bracket power multiply: (am)n = am×n

Think of a cricket BOMB hit — powerful and explosive, just like these index rules! 💥🏏

Mnemonic 2: Hindi Rhyming Trick 🎵

"Ghar ka base ek jaisa, power badhao, multiply kaisa?"

  • Translation: If the base (ghar) is the same, add the powers (badhao).
  • Example: 23 × 24 = 23+4 = 27
  • Just like family members (ghar) sticking together, bases stay same and powers add up! 🏠👨‍👩‍👧‍👦

Mnemonic 3: "INDIA" Acronym for Index Laws 🇮🇳

  • I - Identify same bases
  • N - Negative power means reciprocal
  • D - Divide powers when bases divide: am ÷ an = am-n
  • I - Index of index multiply: (am)n = am×n
  • A - Any number to power zero is 1: a0 = 1

Just like the unity of India, these rules keep indices united and simple! 🇮🇳✨

Interactive

Mission: Master This Topic!

Reinforce what you learned with fun activities

🎯

Ready to Battle? Test Your Knowledge!

Practice MCQs, build combos, climb the leaderboard!

Start Practice

Loading...

Hey! 🔥 Your 7-day streak is at risk. Complete one quick quest today?

Streak broken? No worries. Recover with bonus XP by completing a quest now.