Observe the following number series: 9 8 7 6 5 4 3 2 1 8 7 6 5 4 3 2 1 7 6 5 4 3 2 1. What is the next number that should come after this sequence?

Introduction / Context:
This question checks your ability to identify patterns in a number series. The series is not a simple arithmetic progression; instead, it is built from repeated decreasing blocks. Recognizing how these blocks start and end is the key to predicting the next term. Such series questions are frequently asked in competitive exams to test numerical reasoning and pattern recognition skills.

Given Data / Assumptions:

• The given sequence is: 9 8 7 6 5 4 3 2 1 8 7 6 5 4 3 2 1 7 6 5 4 3 2 1.
• We need the very next number that should follow the last term in this sequence.
• No extra hidden operations such as multiplication or addition are indicated; it appears to be a pure ordering pattern.

Concept / Approach:
The approach is to look for repeated blocks. Notice that the series seems to start at a particular number and then decrease step by step down to 1, then start again at a slightly smaller number and repeat the countdown. By grouping these terms, we can see how the starting number changes from one block to the next and then predict the next starting number after the last complete block. The first term in the next block will be the answer.

Step-by-Step Solution:
Group the numbers from the beginning. The first block is: 9 8 7 6 5 4 3 2 1. The second block is: 8 7 6 5 4 3 2 1. The third block is: 7 6 5 4 3 2 1. Observe that each block is a decreasing sequence that ends at 1. The starting number of each block is decreasing by 1: first 9, then 8, then 7. Therefore the next block should start at 6 and then go down as 6 5 4 3 2 1. The question only asks for the next single number after the given sequence, which is the first number of the next block, namely 6.

Verification / Alternative check:
As a check, write the start of the hypothetical continuation: after the last 1 in the question, the next block would be 6 5 4 3 2 1, followed by another block 5 4 3 2 1, and so on. This extended pattern would remain consistent with the observed rule that each block starts one less than the previous block and decreases down to 1. Since the continuation is coherent, identifying 6 as the first term of the fourth block is correct.

Why Other Options Are Wrong:
Option 9 is wrong because that would restart the pattern at the original highest value instead of following the decreasing starting numbers. Option 8 would be the first term of the second block, but we are already past that. Option 7 is the first term of the third block, which has also already appeared. Option 5 would be the second term of the next block, not the first. Only 6 correctly starts the next block after the given sequence.

Common Pitfalls:
Some candidates may focus on local differences and notice only that many numbers are decreasing by 1, missing the block structure entirely. Others might try to treat the entire series as a single long pattern without grouping, leading to confusion. It is important to look for repeated segments and how they change from one repetition to the next. Once you see that each block is a countdown starting from 9, then 8, then 7, predicting that the next block starts at 6 becomes straightforward.

Final Answer:
The number that should come next in the series is 6.