🔎 Murder mystery / crimeGrade 5Reading: grades 7-9MultiplicationWord problemsMulti-step word problemsFractions of a numberDivision
The Case of the Midnight Ruby
The priceless Midnight Ruby has been stolen from the Blackwood Manor safe during the grand masquerade. It is up to you to analyze the forensic evidence, track the clues, and point out the true thief among the high-society guests.
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 | Signature Tool | Escape Vehicle | Dominant Hand | Wig Color | Undone By |
|---|---|---|---|---|---|
| Nero Wolfe | skeleton key | hot air balloon | left-handed | sleek ink black | camera flash |
| Mycroft Holmes | pocket watch | steam-powered motorcar | left-handed | sleek ink black | scenting hounds |
| Sherlock Holmes | magnifying glass | steam-powered motorcar | right-handed | bright auburn | camera flash |
| Jane Marple | magnifying glass | rowboat on the lake | left-handed | powdered white | squeaky floorboards |
| John Watson | lockpick kit | underground passage | left-handed | bright auburn | camera flash |
| C Auguste Dupin | lockpick kit | steam-powered motorcar | left-handed | sleek ink black | squeaky floorboards |
| Arsene Lupin | pocket watch | stolen carriage | left-handed | sleek ink black | squeaky floorboards |
| Perry Mason | glass cutter | rowboat on the lake | left-handed | sleek ink black | camera flash |
| Sam Spade | glass cutter | stolen carriage | right-handed | powdered white | camera flash |
| Nancy Drew | pocket watch | underground passage | left-handed | sleek ink black | scenting hounds |
| Arthur Conan | pocket watch | stolen carriage | left-handed | powdered white | squeaky floorboards |
| Frank Hardy | skeleton key | steam-powered motorcar | left-handed | powdered white | squeaky floorboards |
| Father Brown | skeleton key | hot air balloon | left-handed | sleek ink black | squeaky floorboards |
| Irene Adler | magnifying glass | rowboat on the lake | right-handed | sleek ink black | squeaky floorboards |
| Ellery Queen | pocket watch | stolen carriage | left-handed | bright auburn | squeaky floorboards |
| James Moriarty | pocket watch | rowboat on the lake | left-handed | sleek ink black | squeaky floorboards |
| Charles Augustus | skeleton key | stolen carriage | right-handed | bright auburn | scenting hounds |
| Philip Marlowe | magnifying glass | steam-powered motorcar | right-handed | sleek ink black | camera flash |
| Reginald Jeeves | magnifying glass | steam-powered motorcar | left-handed | sleek ink black | squeaky floorboards |
| Lois Mitchell | glass cutter | stolen carriage | left-handed | bright auburn | scenting hounds |
| Joe Hardy | pocket watch | rowboat on the lake | right-handed | bright auburn | squeaky floorboards |
Clue 1
Multiplication facts (1-12)
To find the true list of suspects, Detective Sterling must sift through the guest ledger, counting the total guests and subtracting those who left before the heist.
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
49
50
90
T
49
50
8
90
96
14
8
14
9
35
T
49
90
2
22
108
72
90
8
9
108
2
T
49
35
84
90
9
22
108
48
48
8
108
32
90
7 × 7 =T
11 × 2 =C
2 × 7 =D
7 × 12 =L
9 × 10 =E
6 × 12 =P
5 × 10 =H
12 × 9 =A
2 × 1 =S
7 × 5 =O
3 × 3 =N
4 × 2 =I
12 × 8 =F
6 × 8 =R
8 × 4 =G
0/15 letters found
Clue 2
Word problems
To verify the night guard's alibi, we must calculate the total time of his patrol route around the manor's east wing.
Solve each problem to learn its letter, then write the letters in the boxes to fill in the missing word.
Awitnesssawthevillainwas .
L
103
81
98
116
6
119
118
D
81
D
There were 139 footprints. 36 were used up. How many footprints are left?L
There were 150 magnifying glasses. 34 were used up. How many magnifying glasses are left?T
Detective Sterling lined up 9 rows of 9 fingerprints. How many fingerprints in all?E
There were 142 fingerprints. 24 were used up. How many fingerprints are left?N
Detective Sterling lined up 2 rows of 3 clues. How many clues in all?H
Detective Sterling found 109 clues yesterday and 10 more today. How many clues in all?A
There were 123 clues. 25 were used up. How many clues are left?F
0/7 letters found
Clue 3
Multi-step word problems
The butler helps by counting the rows of crystal glasses in the parlor to see how many guests gathered for the midnight toast.
Solve each problem to learn its letter, then write the letters in the boxes to fill in the missing word.
Someonescaredthevillainoffwith .
S
35
69
86
80
59
61
29
F
L
O
O
R
B
O
59
R
D
S
35
Detective Sterling earned 2 magnifying glasses in each of 2 rounds, plus 32 bonus magnifying glasses. Then 1 magnifying glasses were lost. How many magnifying glasses are left?S
There were 435 footprints in all. 22 footprints were set aside. The rest were shared equally among 7 Scotland Yard. How many footprints did each get?A
There were 519 footprints in all. 3 footprints were set aside. The rest were shared equally among 6 Scotland Yard. How many footprints did each get?U
Detective Sterling filled 5 boxes with 4 clues each, then found 60 more clues. How many clues are there in all?E
Detective Sterling collected 22 magnifying glasses in the morning and 65 magnifying glasses in the afternoon, then split them equally among 3 Scotland Yard. How many magnifying glasses did each get?Y
There were 213 footprints in all. 1 Scotland Yard used 6 footprints each. The other 3 Scotland Yard shared the rest equally. How many footprints did each of the other Scotland Yard get?Q
Detective Sterling collected 112 alibis in the morning and 193 alibis in the afternoon, then split them equally among 5 Scotland Yard. How many alibis did each get?K
0/7 letters found
Clue 4
Fractions of a number
We search the study and find a half-burned telegram on the hearth, but only a fraction of its secret message is intact.
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
35
29
22
29
20
12
2
A
35
27
20
11
A
35
22
34
30
A
35
9
9
29
A
35
16
16
25
24
7
29
14
11
25
9
A
35
28
25
3/6 of 70 =A
1/8 of 192 =D
4/8 of 58 =N
3/8 of 32 =B
2/6 of 21 =O
1/4 of 100 =E
2/4 of 60 =W
1/2 of 28 =T
1/8 of 72 =S
2/6 of 6 =L
2/4 of 68 =R
4/8 of 22 =H
1/3 of 66 =I
3/6 of 56 =F
4/10 of 50 =K
1/5 of 80 =G
3/10 of 90 =C
0/17 letters found
Clue 5
Division facts (1-12) — the last clue
The investigation team splits the remaining mud splatters on the carriage paths equally to track which exit route was used.
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
24 ÷ 6 = ?
25 ÷ 5 = ?
7 ÷ 7 = ?
9 ÷ 1 = ?
20 ÷ 2 = ?
33 ÷ 3 = ?
7 ÷ 1 = ?
12 ÷ 6 = ?
72 ÷ 6 = ?
24 ÷ 8 = ?
30 ÷ 5 = ?
Step 2 — cross out the sentence with each answer
1.The villain unlocked the heavy vault using a skeleton key, then drifted over the estate in a hot air balloon.
2.The villain unlocked the heavy vault using a skeleton key, then fled into the night in a stolen carriage.
3.The villain cracked the combination lock with a magnifying glass, then fled into the night in a stolen carriage.
4.The villain slipped past the guards with a lockpick kit, then sped away in a steam-powered motorcar.
5.The villain cracked the combination lock with a magnifying glass, then sped away in a steam-powered motorcar.
6.The villain slipped past the guards with a lockpick kit, then rowed across the dark lake in a rowboat.
7.The villain slipped past the guards with a lockpick kit, then escaped through an underground passage.
8.The villain timed the security patrols using a pocket watch, then rowed across the dark lake in a rowboat.
9.The villain quietly sliced the display case with a glass cutter, then rowed across the dark lake in a rowboat.
10.The villain slipped past the guards with a lockpick kit, then fled into the night in a stolen carriage.
11.The villain unlocked the heavy vault using a skeleton key, then sped away in a steam-powered motorcar.
12.The villain quietly sliced the display case with a glass cutter, then escaped through an underground passage.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Case of the Midnight Ruby
Culprit: James Moriarty (pocket watch · rowboat on the lake · left-handed · sleek ink black · squeaky floorboards)
- Clue 1 (Multiplication facts (1-12)): "THE THIEF DID NOT ESCAPE IN A STOLEN CARRIAGE"7 × 7 = 49 (T) · 11 × 2 = 22 (C) · 2 × 7 = 14 (D) · 7 × 12 = 84 (L) · 9 × 10 = 90 (E) · 6 × 12 = 72 (P) · 5 × 10 = 50 (H) · 12 × 9 = 108 (A) · 2 × 1 = 2 (S) · 7 × 5 = 35 (O) · 3 × 3 = 9 (N) · 4 × 2 = 8 (I) · 12 × 8 = 96 (F) · 6 × 8 = 48 (R) · 8 × 4 = 32 (G)
- Clue 2 (Word problems): "LEFT HANDED"There were 139 footprints. 36 were used up. How many footprints are left? = 103 (L) · There were 150 magnifying glasses. 34 were used up. How many magnifying glasses are left? = 116 (T) · Detective Sterling lined up 9 rows of 9 fingerprints. How many fingerprints in all? = 81 (E) · There were 142 fingerprints. 24 were used up. How many fingerprints are left? = 118 (N) · Detective Sterling lined up 2 rows of 3 clues. How many clues in all? = 6 (H) · Detective Sterling found 109 clues yesterday and 10 more today. How many clues in all? = 119 (A) · There were 123 clues. 25 were used up. How many clues are left? = 98 (F)
- Clue 3 (Multi-step word problems): "SQUEAKY FLOORBOARDS"Detective Sterling earned 2 magnifying glasses in each of 2 rounds, plus 32 bonus magnifying glasses. Then 1 magnifying glasses were lost. How many magnifying glasses are left? = 35 (S) · There were 435 footprints in all. 22 footprints were set aside. The rest were shared equally among 7 Scotland Yard. How many footprints did each get? = 59 (A) · There were 519 footprints in all. 3 footprints were set aside. The rest were shared equally among 6 Scotland Yard. How many footprints did each get? = 86 (U) · Detective Sterling filled 5 boxes with 4 clues each, then found 60 more clues. How many clues are there in all? = 80 (E) · Detective Sterling collected 22 magnifying glasses in the morning and 65 magnifying glasses in the afternoon, then split them equally among 3 Scotland Yard. How many magnifying glasses did each get? = 29 (Y) · There were 213 footprints in all. 1 Scotland Yard used 6 footprints each. The other 3 Scotland Yard shared the rest equally. How many footprints did each of the other Scotland Yard get? = 69 (Q) · Detective Sterling collected 112 alibis in the morning and 193 alibis in the afternoon, then split them equally among 5 Scotland Yard. How many alibis did each get? = 61 (K)
- Clue 4 (Fractions of a number): "AN INK BLACK HAIR WAS SNAGGED ON THE SAFE"3/6 of 70 = 35 (A) · 1/8 of 192 = 24 (D) · 4/8 of 58 = 29 (N) · 3/8 of 32 = 12 (B) · 2/6 of 21 = 7 (O) · 1/4 of 100 = 25 (E) · 2/4 of 60 = 30 (W) · 1/2 of 28 = 14 (T) · 1/8 of 72 = 9 (S) · 2/6 of 6 = 2 (L) · 2/4 of 68 = 34 (R) · 4/8 of 22 = 11 (H) · 1/3 of 66 = 22 (I) · 3/6 of 56 = 28 (F) · 4/10 of 50 = 20 (K) · 1/5 of 80 = 16 (G) · 3/10 of 90 = 27 (C)
- Clue 5 (Division facts (1-12)): surviving statement (box 8) → James Moriarty24 ÷ 6 = 4 · 25 ÷ 5 = 5 · 7 ÷ 7 = 1 · 9 ÷ 1 = 9 · 20 ÷ 2 = 10 · 33 ÷ 3 = 11 · 7 ÷ 1 = 7 · 12 ÷ 6 = 2 · 72 ÷ 6 = 12 · 24 ÷ 8 = 3 · 30 ÷ 5 = 6
About this mystery
- Grade level
- Grade 5 math
- Math topics
- Multiplication, Word problems, Multi-step word problems, Fractions of a number, Division
- Reading level
- grades 7-9
- Theme
- The Case of the Midnight Ruby — set in Blackwood Manor
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects