Digits That Never Decrease
How many six-digit positive integers (from 100000 to 999999) have digits that are non-decreasing from left to right, such as 112399 or 555555? Give an integer.
Related problems & prerequisites
Worth solving first
- Stars and Bars 3.0/10
- PINs Summing to Twenty 3.0/10
Source: Classic counting exercise in wide circulation; no traceable original source. Statement written for AxiomIQ.