🔎 DetectivesGrade 3Reading: grades 3-4MultiplicationPlace valueAdditionRoundingMissing addends
The Case of the Missing Ledger
A secret ledger has been stolen from Detective Academy HQ! The Chief Inspector needs your sharp detective skills to analyze the clues and catch the culprit before they escape.
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 | Specialist Skill | Gadget | Handedness | Disguise Hair | Foiled By |
|---|---|---|---|---|---|
| Enola | Tracking Prints | Voice Changer | Right Handed | Brown Wig | Squeaky Shoes |
| Avery | Disguise Mastery | Night Vision Goggles | Left Handed | Brown Wig | Squeaky Shoes |
| Parker | Eavesdropping | Voice Changer | Right Handed | Brown Wig | Dust Allergy |
| Mason | Disguise Mastery | Night Vision Goggles | Left Handed | Brown Wig | Dust Allergy |
| Cadet Max | Eavesdropping | Voice Changer | Right Handed | Brown Wig | Squeaky Shoes |
| Poirot | Deciphering Codes | Grappling Hook | Right Handed | Blonde Wig | Bright Flashlight |
| Sherlock | Deciphering Codes | Night Vision Goggles | Right Handed | Black Wig | Squeaky Shoes |
| Dupin | Lockpicking | Secret Camera | Left Handed | Brown Wig | Squeaky Shoes |
| Officer Leo | Eavesdropping | Voice Changer | Left Handed | Brown Wig | Squeaky Shoes |
| Nancy | Deciphering Codes | Voice Changer | Left Handed | Brown Wig | Dust Allergy |
| Marple | Disguise Mastery | Voice Changer | Left Handed | Black Wig | Dust Allergy |
| Detective Maya | Disguise Mastery | Night Vision Goggles | Right Handed | Black Wig | Bright Flashlight |
| Gadget | Lockpicking | Voice Changer | Left Handed | Blonde Wig | Squeaky Shoes |
| Marlowe | Tracking Prints | Secret Camera | Right Handed | Brown Wig | Dust Allergy |
| Inspector Rose | Eavesdropping | Night Vision Goggles | Right Handed | Blonde Wig | Squeaky Shoes |
| Agent Maya | Lockpicking | Grappling Hook | Left Handed | Blonde Wig | Dust Allergy |
| Owen | Eavesdropping | Night Vision Goggles | Left Handed | Blonde Wig | Dust Allergy |
| Hardy | Tracking Prints | Night Vision Goggles | Left Handed | Brown Wig | Squeaky Shoes |
| Spade | Tracking Prints | Invisible Ink | Left Handed | Brown Wig | Squeaky Shoes |
| Sleuth Sam | Lockpicking | Voice Changer | Left Handed | Black Wig | Bright Flashlight |
| Wolfe | Eavesdropping | Night Vision Goggles | Right Handed | Black Wig | Dust Allergy |
Clue 1
Multiplication facts (1-12)
You find evidence crates stacked in equal rows inside the evidence locker. Count the rows to uncover a hint.
Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.
T
18
72
108
90
80
90
132
108
63
T
18
84
33
108
90
49
33
T
18
80
90
108
70
90
108
63
14
108
T
18
63
70
22
108
14
70
9 × 2 =T
11 × 2 =M
12 × 9 =E
12 × 7 =D
8 × 9 =H
10 × 7 =A
2 × 7 =R
8 × 10 =U
3 × 11 =O
12 × 11 =P
7 × 7 =N
10 × 9 =S
9 × 7 =C
0/13 letters found
Clue 2
Place value
You check the digit keypad on the vault wall to reveal the place value of the code.
Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.
A
900
9000
7000
300
200
4000
A
900
3000
60
7000
60
400
40
10
3000
200
20
A
900
6000
9000
7000
300
200
600
3000
200
4000
7000
6000
A
900
300
7000
What is the value of the 9 in 977?A
What is the value of the 6 in 8,675?O
What is the value of the 9 in 19,052?L
What is the value of the 6 in 6,285?S
What is the value of the 3 in 359?F
What is the value of the 4 in 9,456?P
What is the value of the 6 in 1,169?D
What is the value of the 2 in 8,425?W
What is the value of the 4 in 24,681?H
What is the value of the 1 in 919?I
What is the value of the 2 in 9,249?T
What is the value of the 4 in 242?R
What is the value of the 7 in 67,816?E
What is the value of the 3 in 43,975?N
0/14 letters found
Clue 3
Addition
You add up all the dropped clues collected from the crime scene footprint grid.
Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.
S
947
861
922
839
795
741
227
S
947
942
224
839
S
947
839
870
942
224
839
744
744
224
307
693
291
942
839
942
795
864
864
307
795
227
338 + 609 =S
473 + 322 =A
288 + 453 =K
297 + 573 =C
498 + 363 =Q
198 + 109 =W
121 + 170 =T
301 + 563 =L
107 + 117 =O
110 + 117 =Y
208 + 485 =N
436 + 308 =D
573 + 266 =E
464 + 478 =H
367 + 555 =U
0/15 letters found
Clue 4
Rounding
The digital radar scanner only shows an estimated rounded signal strength.
Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.
B
500
9000
40
800
2000
700
600
900
9000
800
600
4000
4000
2000
600
300
300
60
5000
40
2000
6000
700
60
5000
40
40
9000
200
600
6000
8000
700
Round 481 to the nearest hundredB
Round 9,484 to the nearest thousandR
Round 5,922 to the nearest thousandT
Round 3,627 to the nearest thousandS
Round 602 to the nearest hundredA
Round 63 to the nearest tenE
Round 264 to the nearest hundredG
Round 782 to the nearest hundredW
Round 5,413 to the nearest thousandD
Round 935 to the nearest hundredI
Round 40 to the nearest tenO
Round 151 to the nearest hundredL
Round 7,860 to the nearest thousandC
Round 2,334 to the nearest thousandN
Round 658 to the nearest hundredH
0/15 letters found
Clue 5
Missing addends — the last clue
You know the total number of missing files and must figure out the missing piece.
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
10 + ___ = 22
4 + ___ = 15
1 + ___ = 10
7 + ___ = 15
8 + ___ = 15
9 + ___ = 11
4 + ___ = 9
7 + ___ = 8
4 + ___ = 10
4 + ___ = 8
7 + ___ = 17
Step 2 — cross out the sentence with each answer
1.The villain tracked prints across the courtyard, then snapped photos with a secret camera.
2.The villain picked the lock to the vault, then tricked the guard with a voice changer.
3.The villain tracked prints across the courtyard, then escaped using night vision goggles.
4.The villain disguised as a junior officer, then left a note in invisible ink.
5.The villain picked the lock to the vault, then left a note in invisible ink.
6.The villain disguised as a junior officer, then tricked the guard with a voice changer.
7.The villain deciphered codes in the ledger, then swung off the roof with a grappling hook.
8.The villain tracked prints across the courtyard, then swung off the roof with a grappling hook.
9.The villain eavesdropped on the secret meeting, then tricked the guard with a voice changer.
10.The villain eavesdropped on the secret meeting, then snapped photos with a secret camera.
11.The villain tracked prints across the courtyard, then left a note in invisible ink.
12.The villain disguised as a junior officer, then escaped using night vision goggles.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Case of the Missing Ledger
Culprit: Hardy (Tracking Prints · Night Vision Goggles · Left Handed · Brown Wig · Squeaky Shoes)
- Clue 1 (Multiplication facts (1-12)): "THE SUSPECT DOES NOT USE A SECRET CAMERA"9 × 2 = 18 (T) · 11 × 2 = 22 (M) · 12 × 9 = 108 (E) · 12 × 7 = 84 (D) · 8 × 9 = 72 (H) · 10 × 7 = 70 (A) · 2 × 7 = 14 (R) · 8 × 10 = 80 (U) · 3 × 11 = 33 (O) · 12 × 11 = 132 (P) · 7 × 7 = 49 (N) · 10 × 9 = 90 (S) · 9 × 7 = 63 (C)
- Clue 2 (Place value): "A LEFT HANDED PRINT WAS LEFT ON THE SAFE"What is the value of the 9 in 977? = 900 (A) · What is the value of the 6 in 8,675? = 600 (O) · What is the value of the 9 in 19,052? = 9000 (L) · What is the value of the 6 in 6,285? = 6000 (S) · What is the value of the 3 in 359? = 300 (F) · What is the value of the 4 in 9,456? = 400 (P) · What is the value of the 6 in 1,169? = 60 (D) · What is the value of the 2 in 8,425? = 20 (W) · What is the value of the 4 in 24,681? = 4000 (H) · What is the value of the 1 in 919? = 10 (I) · What is the value of the 2 in 9,249? = 200 (T) · What is the value of the 4 in 242? = 40 (R) · What is the value of the 7 in 67,816? = 7000 (E) · What is the value of the 3 in 43,975? = 3000 (N)
- Clue 3 (Addition): "SQUEAKY SHOES ECHOED DOWN THE HALLWAY"338 + 609 = 947 (S) · 473 + 322 = 795 (A) · 288 + 453 = 741 (K) · 297 + 573 = 870 (C) · 498 + 363 = 861 (Q) · 198 + 109 = 307 (W) · 121 + 170 = 291 (T) · 301 + 563 = 864 (L) · 107 + 117 = 224 (O) · 110 + 117 = 227 (Y) · 208 + 485 = 693 (N) · 436 + 308 = 744 (D) · 573 + 266 = 839 (E) · 464 + 478 = 942 (H) · 367 + 555 = 922 (U)
- Clue 4 (Rounding): "BROWN HAIR WAS SNAGGED ON THE DOOR LATCH"Round 481 to the nearest hundred = 500 (B) · Round 9,484 to the nearest thousand = 9000 (R) · Round 5,922 to the nearest thousand = 6000 (T) · Round 3,627 to the nearest thousand = 4000 (S) · Round 602 to the nearest hundred = 600 (A) · Round 63 to the nearest ten = 60 (E) · Round 264 to the nearest hundred = 300 (G) · Round 782 to the nearest hundred = 800 (W) · Round 5,413 to the nearest thousand = 5000 (D) · Round 935 to the nearest hundred = 900 (I) · Round 40 to the nearest ten = 40 (O) · Round 151 to the nearest hundred = 200 (L) · Round 7,860 to the nearest thousand = 8000 (C) · Round 2,334 to the nearest thousand = 2000 (N) · Round 658 to the nearest hundred = 700 (H)
- Clue 5 (Missing addends): surviving statement (box 3) → Hardy10 + ___ = 22 = 12 · 4 + ___ = 15 = 11 · 1 + ___ = 10 = 9 · 7 + ___ = 15 = 8 · 8 + ___ = 15 = 7 · 9 + ___ = 11 = 2 · 4 + ___ = 9 = 5 · 7 + ___ = 8 = 1 · 4 + ___ = 10 = 6 · 4 + ___ = 8 = 4 · 7 + ___ = 17 = 10
About this mystery
- Grade level
- Grade 3 math
- Math topics
- Multiplication, Place value, Addition, Rounding, Missing addends
- Reading level
- grades 3-4
- Theme
- The Case of the Missing Ledger — set in Detective Academy HQ
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects