Question 14 of 31intermediate🔍 AnalyzeShort Answer2 marks

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.

Correct Answer

Observation: The digital roots of the sequence will cycle through a pattern.

Key Fact: The digital root of 11 is 2.

Pattern: Starting from any number with digital root d, adding 11 repeatedly gives digital roots: d, d+2, d+4, d+6, d+8, d+1, d+3, d+5, d+7, d, ... (All values taken modulo 9, with 0 becoming 9)

Example: Starting with digital root 1: 1, 3, 5, 7, 9, 2, 4, 6, 8, 1, ...

Conclusion: The sequence cycles through all 9 digital roots (both odd and even), regardless of the starting value. The cycle repeats every 9 additions.

Exercise: Figure it Out (Section 3) | Q: 2 | (Page Page 20)
For More Understanding

Explanation

The chapter discusses digital roots. Since the digital root of 11 is 2, adding 11 repeatedly adds 2 to the digital root each time (modulo 9). This creates a cycling pattern. For example, starting with digital root 1: 1, 3, 5, 7, 9, 2, 4, 6, 8, 1, ... The cycle repeats every 9 additions.

Solution Steps

  1. Find the digital root of 11, which is 2.

  2. Start with any number having digital root d.

  3. Add 11 repeatedly — each addition adds 2 to the digital root (modulo 9).

  4. Observe the pattern: d, d+2, d+4, d+6, d+8, d+1, d+3, d+5, d+7, d, ...

  5. Note: The cycle repeats every 9 additions and covers all 9 digital roots (both odd and even), regardless of the starting value.