🔎 The missing bookGrade 4Reading: grades 3-4Place valueAdditionFractions of a numberSubtractionMissing addends

The Case of the Missing Manuscript

The legendary Golden Book of Riddles has vanished from the vault! The Head Librarian needs your help to find the culprit before the library closes.

Suspects

Possible suspects

Cross off a row as each clue rules it out. On screen, tap a row.

21 of 21 still in play

Name	super scholar power	vault gadget	writing style	ink hair color	silly slip up
Jules Verne	Speed Reading	Feather Quill	Right handed writer	Paper White Hair	Squeaky Boots
J R R Tolkien	Speed Reading	Leather Satchel	Left handed writer	Leather Brown Hair	Squeaky Boots
Paige Turner	Paper Folding	Glowing Magnifier	Left handed writer	Leather Brown Hair	Squeaky Boots
Edgar Poe	Ink Mimicry	Feather Quill	Right handed writer	Leather Brown Hair	Squeaky Boots
Mary Shelley	Bookmark Teleport	Leather Satchel	Right handed writer	Paper White Hair	Sticky Fingers
Emily Dickinson	Paper Folding	Feather Quill	Right handed writer	Ink Blue Hair	Squeaky Boots
Dr Seuss	Paper Folding	Feather Quill	Right handed writer	Ink Blue Hair	Sticky Fingers
Hans Andersen	Paper Folding	Glowing Magnifier	Right handed writer	Leather Brown Hair	Loud Sneezes
Enid Blyton	Bookmark Teleport	Invisibility Dust	Left handed writer	Leather Brown Hair	Sticky Fingers
Charles Dickens	Paper Folding	Glowing Magnifier	Right handed writer	Leather Brown Hair	Squeaky Boots
Louisa Alcott	Ink Mimicry	Invisibility Dust	Left handed writer	Ink Blue Hair	Squeaky Boots
Arthur Conan	Bookmark Teleport	Glowing Magnifier	Right handed writer	Leather Brown Hair	Squeaky Boots
Beatrix Potter	Paper Folding	Invisibility Dust	Right handed writer	Leather Brown Hair	Squeaky Boots
Shel Silverstein	Speed Reading	Invisibility Dust	Right handed writer	Leather Brown Hair	Squeaky Boots
Mark Twain	Speed Reading	Invisibility Dust	Right handed writer	Ink Blue Hair	Loud Sneezes
Jane Austen	Speed Reading	Feather Quill	Left handed writer	Paper White Hair	Sticky Fingers
Bram Stoker	Paper Folding	Invisibility Dust	Right handed writer	Ink Blue Hair	Loud Sneezes
C S Lewis	Speed Reading	Brass Bookmark	Left handed writer	Ink Blue Hair	Loud Sneezes
Robert Stevenson	Paper Folding	Invisibility Dust	Right handed writer	Leather Brown Hair	Sticky Fingers
Lewis Carroll	Bookmark Teleport	Glowing Magnifier	Left handed writer	Paper White Hair	Loud Sneezes
Beverly Cleary	Ink Mimicry	Invisibility Dust	Right handed writer	Paper White Hair	Squeaky Boots

Clue 1

Place value

The thief left a numeric lock code written on a scrap of paper but some digits are in the wrong place value column. Let us fix the place values to open the drawer with the first clue.

Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.

600

5000

200

100

4000

100

600

1000

600

2000

900

5000

700

What is the value of the 2 in 428?T

What is the value of the 6 in 1,962?E

What is the value of the 4 in 4,853?N

What is the value of the 6 in 628?H

What is the value of the 3 in 1,436?A

What is the value of the 7 in 5,751?L

What is the value of the 8 in 680?Q

What is the value of the 5 in 85,792?I

What is the value of the 2 in 2,359?R

What is the value of the 7 in 970?F

What is the value of the 2 in 294?D

What is the value of the 1 in 150?O

What is the value of the 5 in 9,956?S

What is the value of the 9 in 960?U

What is the value of the 1 in 1,282?V

0/15 letters found

Clue 2

Addition

To find the second clue we need to count all the returned adventure novels and mystery novels on the cart. Adding these book stacks together will unlock the next shelf.

Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.

5364

4663

7350

4380

3625

5364

7350

6814

7854

7350

4144

7350

8031

4268

9277

7350

5522

3798

4268

4144

4537

6397

4663

5364

4663

4268

4380

9277

7350

9277

7854

4144

4537

5364

7350

4144

2343 + 3021 =T

1449 + 2931 =N

2271 + 1527 =Y

3127 + 3270 =G

4851 + 2499 =E

3743 + 5534 =D

3099 + 4932 =M

3093 + 1444 =I

4431 + 3423 =W

1719 + 2944 =H

3271 + 3543 =S

2703 + 1441 =R

1775 + 1850 =O

3579 + 1943 =B

2509 + 1759 =A

0/15 letters found

Clue 3

Fractions of a number

The thief tore out a fraction of the pages from a cookbook. If we calculate exactly how many pages are missing out of the total we can read the secret clue written on the spine.

Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.

1/3 of 111 =S

4/10 of 65 =I

2/8 of 52 =H

5/10 of 12 =U

2/4 of 20 =V

5/6 of 42 =G

2/8 of 48 =O

2/10 of 160 =Q

5/8 of 64 =N

1/2 of 48 =A

4/10 of 50 =R

6/10 of 60 =Y

1/6 of 12 =E

2/6 of 57 =W

1/2 of 16 =K

1/4 of 132 =B

2/5 of 70 =P

9/10 of 30 =T

0/18 letters found

Clue 4

Subtraction

The library's bookmark jar is missing many items. Subtract the bookmarks left on the table from the original count to see how many the thief dropped on their way out.

Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.

6408

3810

3889

4346

6376

1411

6156

1411

6156

6408

6017

3298

6156

6857

2440

6857

2305

2575

4346

3298

6408

3889

6857

2575

6408

3810

3683

2305

6017

6156

7943

10772 - 4364 =A

10242 - 4086 =E

3259 - 1848 =L

3810 - 1235 =W

8867 - 4521 =N

7122 - 1105 =T

11330 - 4954 =G

5946 - 2136 =S

8365 - 422 =D

7039 - 3741 =H

5278 - 1389 =I

6054 - 2371 =P

10867 - 4010 =R

3557 - 1252 =O

7323 - 4883 =B

0/15 letters found

Clue 5

Missing addends — the last clue

We need a total of twenty library keycards to lock the doors but some are missing. Solve for the missing number of keycards to secure the room and reveal the final clue.

First solve each problem. Then find each answer in the list below and cross that sentence out. One sentence will be left — that's exactly what the villain did!

Step 1 — solve these

18 + ___ = 26

22 + ___ = 25

15 + ___ = 16

19 + ___ = 31

32 + ___ = 41

35 + ___ = 41

33 + ___ = 40

4 + ___ = 15

23 + ___ = 33

7 + ___ = 9

35 + ___ = 39

Step 2 — cross out the sentence with each answer

1.The villain swipes the ancient scroll, then hides inside a giant encyclopedia.

2.The villain tiptoes over the creaky floorboards, then hides inside a giant encyclopedia.

3.The villain cracks the secret vault lock, then hides inside a giant encyclopedia.

4.The villain slips past the security owl, then escapes into the stormy night.

5.The villain sneaks through the comic section, then flees out the library window.

6.The villain swipes the ancient scroll, then zips away on a flying book.

7.The villain sneaks through the comic section, then zips away on a flying book.

8.The villain swipes the ancient scroll, then flees out the library window.

9.The villain sneaks through the comic section, then scampers down the spiral stairs.

10.The villain tiptoes over the creaky floorboards, then flees out the library window.

11.The villain slips past the security owl, then zips away on a flying book.

12.The villain tiptoes over the creaky floorboards, then escapes into the stormy night.

Solve it

Name the culprit

Choose the one suspect left standing.

Answer Key — The Case of the Missing Manuscript

Culprit: Arthur Conan (Bookmark Teleport · Glowing Magnifier · Right handed writer · Leather Brown Hair · Squeaky Boots)

Clue 1 (Place value): "THE THIEF DOES NOT HAVE A FEATHER QUILL"
What is the value of the 2 in 428? = 20 (T) · What is the value of the 6 in 1,962? = 60 (E) · What is the value of the 4 in 4,853? = 4000 (N) · What is the value of the 6 in 628? = 600 (H) · What is the value of the 3 in 1,436? = 30 (A) · What is the value of the 7 in 5,751? = 700 (L) · What is the value of the 8 in 680? = 80 (Q) · What is the value of the 5 in 85,792? = 5000 (I) · What is the value of the 2 in 2,359? = 2000 (R) · What is the value of the 7 in 970? = 70 (F) · What is the value of the 2 in 294? = 200 (D) · What is the value of the 1 in 150? = 100 (O) · What is the value of the 5 in 9,956? = 50 (S) · What is the value of the 9 in 960? = 900 (U) · What is the value of the 1 in 1,282? = 1000 (V)
Clue 2 (Addition): "THE NOTES WERE MADE BY A RIGHT HANDED WRITER"
2343 + 3021 = 5364 (T) · 1449 + 2931 = 4380 (N) · 2271 + 1527 = 3798 (Y) · 3127 + 3270 = 6397 (G) · 4851 + 2499 = 7350 (E) · 3743 + 5534 = 9277 (D) · 3099 + 4932 = 8031 (M) · 3093 + 1444 = 4537 (I) · 4431 + 3423 = 7854 (W) · 1719 + 2944 = 4663 (H) · 3271 + 3543 = 6814 (S) · 2703 + 1441 = 4144 (R) · 1775 + 1850 = 3625 (O) · 3579 + 1943 = 5522 (B) · 2509 + 1759 = 4268 (A)
Clue 3 (Fractions of a number): "SQUEAKY BOOTS GAVE AWAY THEIR POSITION"
1/3 of 111 = 37 (S) · 4/10 of 65 = 26 (I) · 2/8 of 52 = 13 (H) · 5/10 of 12 = 6 (U) · 2/4 of 20 = 10 (V) · 5/6 of 42 = 35 (G) · 2/8 of 48 = 12 (O) · 2/10 of 160 = 32 (Q) · 5/8 of 64 = 40 (N) · 1/2 of 48 = 24 (A) · 4/10 of 50 = 20 (R) · 6/10 of 60 = 36 (Y) · 1/6 of 12 = 2 (E) · 2/6 of 57 = 19 (W) · 1/2 of 16 = 8 (K) · 1/4 of 132 = 33 (B) · 2/5 of 70 = 28 (P) · 9/10 of 30 = 27 (T)
Clue 4 (Subtraction): "A SINGLE LEATHER BROWN HAIR WAS SPOTTED"
10772 - 4364 = 6408 (A) · 10242 - 4086 = 6156 (E) · 3259 - 1848 = 1411 (L) · 3810 - 1235 = 2575 (W) · 8867 - 4521 = 4346 (N) · 7122 - 1105 = 6017 (T) · 11330 - 4954 = 6376 (G) · 5946 - 2136 = 3810 (S) · 8365 - 422 = 7943 (D) · 7039 - 3741 = 3298 (H) · 5278 - 1389 = 3889 (I) · 6054 - 2371 = 3683 (P) · 10867 - 4010 = 6857 (R) · 3557 - 1252 = 2305 (O) · 7323 - 4883 = 2440 (B)
Clue 5 (Missing addends): surviving statement (box 5) → Arthur Conan
18 + ___ = 26 = 8 · 22 + ___ = 25 = 3 · 15 + ___ = 16 = 1 · 19 + ___ = 31 = 12 · 32 + ___ = 41 = 9 · 35 + ___ = 41 = 6 · 33 + ___ = 40 = 7 · 4 + ___ = 15 = 11 · 23 + ___ = 33 = 10 · 7 + ___ = 9 = 2 · 35 + ___ = 39 = 4

About this mystery

Grade level: Grade 4 math
Math topics: Place value, Addition, Fractions of a number, Subtraction, Missing addends
Reading level: grades 3-4
Theme: The Case of the Missing Manuscript — set in The Whispering Library Vault
Format: Interactive online & printable worksheet with answer key
Solution: One unique, verified culprit among 21 suspects

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