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Everything about Digital root

Repeated sum of a number's digits

The digital root of a natural number in a given radix is the value obtained by an iterative process of summing digits, on each iteration using the result from the previous iteration to compute a digit sum. The process continues until a single-digit number is reached. For example, in base 10, the digital root of the number 12345 is 6 because the sum of the digits in the number is 1 + 2 + 3 + 4 + 5 = 15, then the addition process is repeated for the resulting number 15, so that the sum of 1 + 5 equals 6, which is the digital root of that number. In base 10, this is equivalent to taking the remainder upon division by 9, which allows it to be used as a divisibility rule. Generally, the digital root computed in integer base b ≥ 2 of a non-negative integer n satisfies Wikipedia →

🧭 Start here: a 6-step reading path

  1. Read the overview: Digital rootA 5-minute orientation
  2. Skim a recent paper: Real-Time Analysis of Multiple Root Causes for Anomalies Assisted by Digital Twin in NFV EnvironmentInfluential work since 2022
  3. Pick up a classic book: Principles of internal medicineThe most-reprinted book on the subject
  4. Read the landmark paper: Digital imaging of root traits (DIRT): a high-throughput computing and collaboration platform for field-based root phenomicsCited 169 times
  5. Go sideways: Multiplicative digital rootA closely related topic
  6. Go sideways: Dudeney numberA closely related topic

📖 Definitions

Noun The single digit obtained from a number by repetitive digitaddition

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  1. Formal definition
  2. Direct formulas
  3. Properties
  4. Additive persistence
  5. Programming example
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🏆 Landmark papers (most cited)

🆕 Influential since 2022

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