June | 2023 | Python Adventures

Sum the digits of a number until you get just one digit

June 7, 2023 Jabba Laci Leave a comment

Problem

Take a positive integer and sum its digits. Repeat this process until you get just one digit.

Example: 1472 🠖 1+4+7+2 = 14 🠖 1+4 = 5. The answer is 5.

Solution

# Python code
n = 1472
result = ((n-1) % 9) + 1

Credits

Thanks to my friend Mocsa who told me this math trick.

Categories: python Tags: math, sum, trick