# Dewey Decimal System Day (Holiday Hoopla 2023)

Dewey Decimal System Day
Holiday Hoopla 2023
Statistics
No. solves69
No. total guesses125

Dewey Decimal System Day is a logic puzzle from Holiday Hoopla 2023. Its difficulty level is categorized as Medium relative to the other puzzles in the hunt.

The puzzle is presented as a series of images of books on shelves.

## Solve Path

Each book has a title and a decimal number below it.

The flavor text indicates that "some books are mislabeled." Searching up the titles of some of the books in the puzzle reveals that the book titles are fictitious.

However, it is still possible to infer what the books are about and verify if they are correctly classified according to the the Dewey Decimal System.

Solvers can use various resources to check the category associated with each decimal number. The solution below will use links to LibraryThing.com.

Verifying the classification of the books on the first shelf
Book Title Dewey Decimal Number Category Associated with Number Correctly Classified?
1 There are Three Holes in a Pretzel: An Introduction to Topology 001.98 Conspiracy Theories No
2 Are You Financially Stable? Introduction to Microeconomics 003.52 Perception Theory No
3 Two Paradigms of Computer Languages 005.13 Computer Programming Languages Yes
4 Types of Public Libraries in the US 027.47 Public Libraries in North America Yes
5 Of Age: Psychological Research on Growing Adolescents 155.51 General Adolescent Psychology Yes

Verifying the classification of the books on the second shelf
Book Title Dewey Decimal Number Category Associated with Number Correctly Classified?
1 Nonfiction and Education: Effective Use of Literature in the Classroom 174.25 Bioethics No
2 Books Unearthed: Historical Records of Ancient Architecture 199.66 Philosophy of West Africa No
3 In God's Name: Religion in the Classroom 200.71 Religious Education, Curricula Yes
4 The Evolution of Fantasy: Myths and Folklores 248.85 Christian Living for the Elderly No
5 Shelves of Policies: Democracy in the United States 320.97 Political Situation and Conditions (North America) Yes

Verifying the classification of the books on the third shelf
Book Title Dewey Decimal Number Category Associated with Number Correctly Classified?
1 Ones and Zeros: The Spread of Digital Information 345.73 U.S. Criminal Law No
2 That Calls for a Celebration: Social Customs at Mardi Gras 394.25 Carnival Holiday Yes
3 Match in Meaning: Linguistic Semantics 401.43 Semantics Yes
4 Their, There, They're: Understanding Grammar 428.24 English as a Second Language - Applied Linguistics Yes
5 Number Theory: Of Integers and Functions 493.10 Old Egyptian Philology No

Verifying the classification of the books on the fourth shelf
Book Title Dewey Decimal Number Category Associated with Number Correctly Classified?
1 Category 5: Catastrophic Hurricanes 551.55 Storms Yes
2 And The Music Played On: A Melodic Journey Through History 567.90 Dinosaurs No
3 Those Same Differences: American Cultural Diaspora 599.86 Old World Monkeys No
4 Which Foods Should I Put in My Body? A Guide to Eating Healthier 613.21 Dietaries Yes
5 Don't Plagiarize: How to Cite Sources Properly 690.83 Conventional Housing No

Verifying the classification of the books on the fifth shelf
Book Title Dewey Decimal Number Category Associated with Number Correctly Classified?
1 Use the Correct Tools: Guidebook for Household Cleaning 759.03 The Renaissance Period No
2 Library of Autonomy: The Emergence of Self-driving Vehicles 782.14 Musicals No
3 Thing of Destiny: Unraveling Themes of Greek Literature 880.93 Themes and Subjects of Greek Literature Yes
4 Melvil: An Autobiography 880.01 Classic Greek Literature No
5 Site Seekers: Exploring the Wonders of Manchuria 915.18 Geography of Manchuria and Travel in Manchuria Yes

The second sentence in the flavor text tells solvers "Finally for each shelf base, two is the magic number." It is possible to interpret each shelf of books as a base-2 (binary) number, where each correctly-classified book is represented as 1 and as 0 otherwise.

Solvers can convert each shelf's five-digit binary number to its decimal value and subsequently use A1Z26 to extract a letter.

Extracting the answer using 5-bit binary
Shelf Correctly Classified? As Binary Value in Decimal A1Z26
1 No, No, Yes, Yes, Yes 00111 7 G
2 No, No, Yes, No, Yes 00101 5 E
3 No, Yes, Yes, Yes, No 01110 14 N
4 Yes, No, No, Yes, No 10010 18 R
5 No, No, Yes, No, Yes 00101 5 E

These letters spell out the answer Click to revealGENRE.

## Puzzle Elements

Dewey Decimal System - This is the theme of this puzzle.

Binary - Extraction makes use of 5-bit binary.