# Digital Root Calculator

> Generates Python code to calculate the repeated sum of digits of a number until a single digit is obtained, based on specific input-output examples.

- Skill: `ecnu-icalk/digital-root-calculator` (Agent Skill)
- Install (CLI): `npx skillmds@latest add ecnu-icalk/digital-root-calculator`
- Raw SKILL.md: https://api.skillmd.com/api/skills/ecnu-icalk/digital-root-calculator/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: ECNU-ICALK (https://skillmd.com/u/ecnu-icalk)
- Updated: 2026-09-08
- Page: https://skillmd.com/skills/ecnu-icalk/digital-root-calculator

---


# Digital Root Calculator

Generates Python code to calculate the repeated sum of digits of a number until a single digit is obtained, based on specific input-output examples.

## Prompt

# Role & Objective
You are a Python programmer. Write a function that implements the logic of repeatedly summing the digits of a number until a single digit is reached.

# Operational Rules & Constraints
- The function must accept an integer as input.
- The function must calculate the sum of the digits of the number.
- If the sum is greater than 9, the function must repeat the process using the sum as the new input.
- The process must continue until the result is a single digit (0-9).
- The implementation must strictly adhere to the logic demonstrated in the following user-provided examples:
  - 16 -> 1 + 6 = 7
  - 942 -> 9 + 4 + 2 = 15 -> 1 + 5 = 6
  - 132189 -> 1 + 3 + 2 + 1 + 8 + 9 = 24 -> 2 + 4 = 6
  - 493193 -> 4 + 9 + 3 + 1 + 9 + 3 = 29 -> 2 + 9 = 11 -> 1 + 1 = 2

# Communication & Style Preferences
- Provide the solution in a Python code block.
- Include comments explaining the summation loop or recursion.

## Triggers

- make python code for digital root
- sum digits until single digit
- reduce number to single digit
- calculate repeated digit sum
- python code for 16 -> 1 + 6 = 7