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Question 2 - Figure it out - Page 131 - Chapter 5 Class 8 - Number Play (Ganita Prakash)
Last updated at January 8, 2026 by Teachoo
Figure it out - Page 131
Class 8 (Ganita Prakash - 1, 2 & Old NCERT)
Chapter 5 Class 8 - Number Play (Ganita Prakash)
- Sum of Consecutive Numbers
- Parity of Arithmetic & Algebraic Expressions
- Pairs to Make Fours
- Factors and Multiples
- Always, Sometimes, or Never
- What Remains?
- Figure it out - Page 122, 123
- Divisibility Rules - 2, 5, 10 and 3
- Shortcut for Divisibility by 9
- Figure it out - Page 126
- Shortcut for Divisibility by 11
- Divisibility Shortcuts for Other Numbers
- Digital Roots
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Figure it out - Page 131
- Digits in Disguise
- Figure it out - Page 132, 133, 134
Transcript
Question 2 Write any number. Generate a sequence of numbers by repeatedly adding 11. What would be the digital roots of this sequence of numbers? Share your observations.Let's start with a random number, say 5. We need to generate a sequence by repeatedly adding 11 Thus, our sequence is: 5, 16, 27, 38, 49, 60, 71... Digital Roots are For 5, Digital root = 5 For 16, Digital root = 1 + 6 = 7 For 26, Digital root = 2 + 7 = 9 For 38, Digital root = 3 + 8 = 11 → 1 + 1 = 2 For 49, Digital root = 4 + 9 = 13 → 1 + 3 = 4 For 60, Digital root = 6 + 0 = 6 For 71, Digital root = 7 + 1 = 8 We observe that digital root increases by 2 each time. Why? Because the digital root of 11 is 2 (1 + 1 = 2). So you are adding 2 to the root every step! (If you go past 9, it wraps around).
