NCERT · Class 6 · Mathematics · Playing with NumbersWhat is the Highest Common Factor (HCF) of 20, 28, and 36?
Step-by-Step Solution
To find the HCF, write the prime factorisation of each number:
- $20 = 2 \times 2 \times 5 = 2^2 \times 5$
- $28 = 2 \times 2 \times 7 = 2^2 \times 7$
- $36 = 2 \times 2 \times 3 \times 3 = 2^2 \times 3^2$ \nThe common prime factor with the lowest power is $2^2 = 4$.\nTherefore, $\text{HCF}(20, 28, 36) = 4$.
Detailed Options Breakdown
Option : 2
Incorrect choice. This distractor represents a common misunderstanding of the core principles of Playing with Numbers.
Option 1: 4 (Correct Answer)
Correct choice. Refer to the step-by-step verified solution guidelines above for details.
Option 2: 6
Incorrect choice. This distractor represents a common misunderstanding of the core principles of Playing with Numbers.
Option 3: 8
Incorrect choice. This distractor represents a common misunderstanding of the core principles of Playing with Numbers.
💡 Study Guide: This question tests core syllabus concepts from Playing with Numbers. For formulas, key summaries, and mock exam reference guides, read the full Playing with Numbers Revision Notes.