CBSE Class 8 Mathematics Question 5 of 16

Number Play — Question 5

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5
Question
“I hold some pebbles, not too many, when I group them in 3’s, one stays with me. Try pairing them up — it simply won’t do. A stubborn odd pebble remains in my view. Group them by 5, yet one’s still around, but grouping by seven, perfection is found. More than one hundred would be far too bold. Can you tell me the number of pebbles I hold?”
Answer

The LCM of 3, 5, and 7 = 3 × 5 × 7 = 105 [∵ 3, 5, and 7 are prime numbers] No. of pebbles = 105 + 1 = 106


Source: This question is from Number Play, Mathematics — Class 8, CBSE Board.

Key Concepts Covered

This question tests your understanding of the following concepts from the chapter Number Play: Hold, Pebbles, Too, Group, Stays, Try. These are fundamental topics in Mathematics that students are expected to master as part of the CBSE Class 8 curriculum.

A thorough understanding of these concepts will help you answer similar questions confidently in your CBSE examinations. These topics are frequently tested in both objective and subjective sections of Mathematics papers. We recommend revising the relevant section of your textbook alongside practising these solved examples to build a strong foundation.

How to Approach This Question

Read the question carefully and identify what is being asked. Break down complex questions into smaller parts. Use the terminology and concepts discussed in this chapter. Structure your answer logically — begin with a definition or key statement, then provide supporting details. Review your answer to ensure it addresses all parts of the question completely.

Key Points to Remember

  • Always show your working steps clearly.
  • Verify your answer by substituting values back into the equation.
  • Practice similar problems from the textbook exercises.
  • Memorise important formulae and their conditions of applicability.

Practice more questions from Number Play — Mathematics, Class 8 CBSE