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Finding Cube of a Large Numbers
Last updated at July 30, 2025 by Teachoo
Class 8 (Ganita Prakash & Old NCERT)
Chapter 1 Class 8 - A Square and a Cube (Ganita Prakash)
- Introduction
- Square Numbers
- Perfect Squares - and its Properties
- Perfect Squares - and its Patterns
- Square Root
- Smallest number multiply or divide to get perfect square
- Estimating Square Root
- Figure it out - Page 10, 11
-
Cubic Numbers
- Perfect Cubes - and its Properties
- Perfect Cubes - and its Patterns
- Cube Root
- Smallest number multiply or divide to get perfect cube
- A pinch of History
- Figure it out - Page 16, 17
Transcript
Finding Cube of Large Numbers Find Cube of 23 233 = 23 × 23 × 23 = (20 + 3) × (20 + 3) × (20 + 3) = (20 + 3)3 Using (a + b)3 = a3 + b3 + 3ab (a + b) = 8000 + 27 + 180 × 23 = 8000 + 27 + 4140 = 12,167 Find Cube of 39 393 = 39 × 39 × 39 = (40 – 1) × (40 – 1) × (40 – 1) = (40 – 1)3 Using (a – b)3 = a3 – b3 – 3ab (a – b) = 403 – 13 – 3 × 40 × 1 (40 – 1) = 64000 – 1 – 120 × 39 = 64000 – 1 – 4680 = 64000 – (1 + 4680) = 64000 – 4681 = 59,319
