Intelligent Math Puzzle – Challenge 81
Enjoy solving math puzzles and critical thinking challenges? If so, then this challenge is just for you. The answer is also given.

Challenge:
What is the last number in the 18th row in the following pattern?
First row: 2
Second row: 3 4
Third row: 5 6 7
Fourth row: 8 9 10 11
…
A- 169
B- 170
C- 171
D- 172
E- 173
The Absolute Best Book to Challenge Your Smart Student!

The correct answer is D.
Each row has one number more than the previous row. The first row has one number, the second row has two numbers, and the 18th row has 18 numbers.
To answer the question, we should find the number of numbers in all 18 rows.
\(1 + 2 + 3 + … + 17 + 18 = \frac{18}{2}(1+18) = 171\)
The first number starts with 2. Therefore, the last number is 172 (171 +1).The Best Books to Ace Algebra
Original price was: $29.99.$14.99Current price is: $14.99.Original price was: $29.99.$14.99Current price is: $14.99.Satisfied 1 StudentsOriginal price was: $24.99.$14.99Current price is: $14.99.Satisfied 92 StudentsOriginal price was: $24.99.$15.99Current price is: $15.99.Satisfied 125 Students
Related to This Article
More math articles
- Complete Guide to Foundational Vector Operations: Addition, Scaling, and More
- Best Online Math Tutoring Devices
- 3rd Grade SBAC Math FREE Sample Practice Questions
- 10 Most Common ACCUPLACER Math Questions
- What Skills Do I Need for the SAT Math Test?
- Students Effective Use of Math Skills in Other Academic Disciplines
- Top 10 Accuplacer Math Prep Books (Our 2023 Favorite Picks)
- How to Master Work Problems: A Comprehensive Step-by-Step Guide
- 3rd Grade STAAR Math FREE Sample Practice Questions
- Algebra Puzzle – Challenge 40
What people say about "Intelligent Math Puzzle – Challenge 81 - Effortless Math: We Help Students Learn to LOVE Mathematics"?
No one replied yet.