Q: What is the digital root of 399,870
A: 9
The digital root of a number is calculated by splitting the digits of a number and then adding them together. You keep splitting and adding the digits until you reach a single positive number.
Split the number up and add each digit together:
If the answer is more than one digit, you would add each digit of the answer together again:
What is the digital root of number 399,870?
Answer: 9