Class 8 Maths – Chapter 7
Cubes and Cube Roots

Simple Notes for Easy Learning

1️⃣ Cube of a Number

The cube of a number is obtained by multiplying the number three times.

Formula: n³ = n × n × n

Examples:

• 2³ = 2 × 2 × 2 = 8
• 3³ = 27
• 5³ = 125

2️⃣ Cube Numbers

Numbers obtained by cubing natural numbers are called cube numbers.

Examples: 1, 8, 27, 64, 125, 216

3️⃣ Properties of Cube Numbers

• Cube of an even number is even
• Cube of an odd number is odd
• Cubes end only with digits 0–9 (no restriction like squares)

4️⃣ Cube Root

Cube root of a number is the number whose cube is the given number.

Symbol: ∛

Examples:

• ∛8 = 2
• ∛27 = 3
• ∛64 = 4

5️⃣ Finding Cube Root by Prime Factorisation

Step 1: Write the number as product of prime factors.
Step 2: Make groups of three equal factors.
Step 3: Take one factor from each group.

Example:

∛216 = ∛(2×2×2×3×3×3)
= 2 × 3 = 6

6️⃣ Perfect Cube Numbers

Numbers whose cube roots are whole numbers are called perfect cubes.

Examples: 1, 8, 27, 64, 125, 216, 343

⭐ Exam Tips for Students

• Memorize cubes from 1 to 10
• Always group factors in threes
• Underline final answers

📘 Prepared by Shaktimatha Learning | Class 8 Maths