Among the three digit numbers 431, 936, 871 and 652, identify the odd one out based on the order of digits.

Introduction / Context:
In digit pattern problems, the odd one out is often found by observing the order of digits within each number. The digits might be strictly increasing, strictly decreasing or follow some other simple relation. In this question, four three digit numbers are given and we must identify which one has a different internal order of digits compared to the others.

Given Data / Assumptions:
The numbers are 431, 936, 871 and 652. We treat each number as a sequence of three digits. We compare whether the digits from left to right form a strictly decreasing order.

Concept / Approach:
The key idea is to check each number for monotonically decreasing digits, that is, each subsequent digit must be smaller than the previous one. If three numbers have digits in strictly decreasing order and one number does not, the one that breaks this rule is the odd one out. Such descending order patterns are very common in number series and odd one out questions.

Step-by-Step Solution:
Step 1: For 431, the digits are 4, 3 and 1. We see that 4 > 3 and 3 > 1, so the digits are strictly decreasing. Step 2: For 936, the digits are 9, 3 and 6. 9 > 3, but 3 is not greater than 6. Here the sequence goes down from 9 to 3, then up from 3 to 6, so it is not strictly decreasing. Step 3: For 871, the digits are 8, 7 and 1. Since 8 > 7 and 7 > 1, this sequence is strictly decreasing. Step 4: For 652, the digits are 6, 5 and 2. We have 6 > 5 and 5 > 2, so this is also strictly decreasing. Step 5: Three numbers 431, 871 and 652 have digits in strictly decreasing order, while 936 breaks this pattern. Therefore 936 is the odd one out.

Verification / Alternative check:
We can verify again by quickly writing the inequality chain for each number: 4 > 3 > 1, 9 > 3 < 6, 8 > 7 > 1, 6 > 5 > 2. Only for 936 does the chain not show continuous decreasing order, which confirms our reasoning. No other simple digit based pattern, such as sums or products of digits, gives as clear a distinction as the order comparison here.

Why Other Options Are Wrong:
431 is not the odd one out because its digits follow a perfect decreasing sequence. 871 is not the odd one out because it also has strictly decreasing digits. 652 is not the odd one out because it shares the same decreasing order property. 936 is alone in not having a monotonic decrease, which makes it different.

Common Pitfalls:
A typical mistake is to focus on the overall magnitude or divisibility of the numbers instead of the internal digit pattern. Some candidates may misread digits quickly under time pressure and miss the increase from 3 to 6 in 936. Practicing with digit order patterns helps in quickly spotting such irregularities in competitive exams.

Final Answer:
The number whose digits do not form a strictly decreasing sequence and is therefore the odd one out is 936.