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Question 1 - Figure it out - Page 132, 133, 134 - Chapter 5 Class 8 - Number Play (Ganita Prakash)
Last updated at January 8, 2026 by Teachoo
Figure it out - Page 132, 133, 134
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
- Figure it out - Page 131
- Digits in Disguise
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Figure it out - Page 132, 133, 134
Transcript
Question 1 If 31z5 is a multiple of 9, where z is a digit, what is the value of z? Explain why there are two answers to this problem.We know that, A Number is divisible by 9, if sum of digits is divisible by 9 31z5 Sum of digits = 3 + 1 + z + 5 = 9 + z Let us check different values of z & check if number is divisible by 9 Sum of digits = 9 + z ∴ z can be 0 or 9 ∴ The required numbers are 3105 or 3195. There are two answers to this problem because both 3105 and 3195 have digital roots 9 , which is divisible by 9 .
