Question 7 of 47intermediate💡 UnderstandEssay2 marks

This halving and doubling strategy works well when we have to multiply with numbers like 5 and 25. Discuss why?

Correct Answer

The halving and doubling strategy works well with 5 and 25 because when you double these numbers, you get 10 and 50 respectively, which are much easier to multiply with.

Multiplying by 10 or 50 simply requires adding zeros, making mental calculation much faster and less error-prone.

Exercise: Doubling and Halving | Q: 2 | (Page Page 7)
For More Understanding

Explanation

The chapter explains that 5 and 25 are special numbers because their doubles (10 and 50) create friendly numbers for multiplication. This reduces computational complexity.

Solution Steps

  1. Doubling 5 gives 10, doubling 25 gives 50

  2. 10 and 50 are easier to multiply with

  3. Multiplying by 10 or 50 requires adding zeros

  4. Mental calculation becomes faster and less error-prone

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