Grade 5Reading: grades 3-4Fractions of a numberOrder of operationsMultiplicationRoundingDivision
The Case of the Missing Compass Rose
Someone snuck into the chart room at Sapphire Cove Island Academy and stole the ancient Compass Rose! Solve the clues to reveal who did it.
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 | Naval Power | Exploration Gear | Writing Hand | Hair Style | Vulnerability |
|---|---|---|---|---|---|
| Soren Blake | Wind Whispering | Glider Wings | Left-handed writer | Spiky red hair | Loud foghorns |
| Liam Archer | Current Control | Grappling Hook | Right-handed writer | Spiky red hair | Bright flashlights |
| Hugo Thorne | Star Reading | Fog Lantern | Left-handed writer | Spiky red hair | Loud foghorns |
| Elena Vance | Wind Whispering | Pocket Telescope | Left-handed writer | Spiky red hair | Loud foghorns |
| Finn Oakley | Tide Bending | Pocket Telescope | Left-handed writer | Spiky red hair | Salty sea breeze |
| Riley Hayes | Star Reading | Grappling Hook | Right-handed writer | Braided brown hair | Loud foghorns |
| Mia Holloway | Wind Whispering | Glider Wings | Left-handed writer | Spiky red hair | Salty sea breeze |
| Olivia West | Current Control | Grappling Hook | Left-handed writer | Curly black hair | Salty sea breeze |
| Nico Rivers | Map Manipulation | Pocket Telescope | Left-handed writer | Braided brown hair | Loud foghorns |
| Scout Nora | Current Control | Brass Compass | Left-handed writer | Spiky red hair | Salty sea breeze |
| Explorer Ivy | Wind Whispering | Brass Compass | Left-handed writer | Braided brown hair | Loud foghorns |
| Mateo Cruz | Wind Whispering | Pocket Telescope | Right-handed writer | Curly black hair | Salty sea breeze |
| Cadet Maya | Star Reading | Brass Compass | Left-handed writer | Curly black hair | Bright flashlights |
| Captain Barnaby | Star Reading | Glider Wings | Right-handed writer | Braided brown hair | Salty sea breeze |
| Navigator Sam | Tide Bending | Grappling Hook | Left-handed writer | Spiky red hair | Salty sea breeze |
| Piper Finch | Wind Whispering | Glider Wings | Right-handed writer | Spiky red hair | Salty sea breeze |
| Rookie Jonah | Map Manipulation | Glider Wings | Left-handed writer | Curly black hair | Salty sea breeze |
| Jasper Drake | Star Reading | Fog Lantern | Right-handed writer | Curly black hair | Salty sea breeze |
| Skipper Zoe | Map Manipulation | Pocket Telescope | Left-handed writer | Spiky red hair | Salty sea breeze |
| Kira Sterling | Tide Bending | Fog Lantern | Left-handed writer | Curly black hair | Bright flashlights |
| Quinn Baxter | Star Reading | Glider Wings | Left-handed writer | Spiky red hair | Loud foghorns |
Clue 1
Fractions of a number
We searched the island workshop map. Only a fraction of the total supply crates were untouched.
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
19
21
18
12
27
4
4
26
27
38
13
7
18
32
38
7
T
19
17
26
14
14
16
26
11
14
26
32
32
17
7
29
2
26
32
32
1/5 of 95 =T
2/10 of 80 =Y
2/3 of 18 =V
3/6 of 34 =C
2/10 of 105 =H
4/6 of 48 =S
4/8 of 26 =D
2/6 of 42 =R
2/6 of 54 =E
2/4 of 8 =L
2/3 of 39 =A
3/6 of 54 =I
3/6 of 58 =M
1/3 of 114 =N
2/5 of 5 =P
2/6 of 21 =O
1/10 of 110 =B
0/17 letters found
Clue 2
Order of operations
To unlock the captain's desk, we had to follow a strict order of steps on the lock tumbler.
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
40
61
76
16
48
59
59
11
48
49
18
48
62
49
76
41
T
40
61
76
49
31
T
40
76
34
48
T
40
61
11
59
76
30
T
40
61
11
49
41
5 × 12 - 20 =T
8 × 8 - 16 =I
12 × 3 - 20 =V
56 + 5 × 4 =E
7 × 11 - 28 =N
5 × 12 - 26 =W
2 × 10 - 9 =A
6 × 12 - 10 =G
8 × 4 - 1 =O
3 × 12 - 6 =F
3 × 10 - 12 =S
12 × 7 - 23 =H
7 × 10 - 29 =D
10 × 8 - 21 =L
0/14 letters found
Clue 3
Multiplication facts (1-12)
The harbor master counted identical stacks of sea charts lined up in equal rows across the desk.
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
44
11
48
110
28
48
27
33
90
100
48
48
110
90
70
120
2
27
110
27
100
T
44
45
110
48
27
8
70
48
48
84
48
11 × 4 =T
11 × 10 =S
3 × 9 =A
10 × 10 =L
12 × 4 =E
1 × 11 =H
3 × 11 =K
5 × 9 =Y
12 × 10 =O
10 × 9 =F
4 × 7 =N
8 × 1 =B
12 × 7 =Z
7 × 10 =R
2 × 1 =M
0/15 letters found
Clue 4
Rounding
The ship's digital echo sounder only shows rounded depth measures to the nearest ten feet.
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
2900
230
3700
50
430
370
1100
90
20
9000
3700
370
500
9000
S
2900
200
1100
3000
700
9000
700
700
20
1100
S
2900
900
1100
4300
1100
Round 2,919 to the nearest hundredS
Round 48 to the nearest tenK
Round 942 to the nearest hundredC
Round 234 to the nearest tenP
Round 8,680 to the nearest thousandA
Round 657 to the nearest hundredT
Round 483 to the nearest hundredW
Round 86 to the nearest tenD
Round 4,274 to the nearest hundredN
Round 179 to the nearest hundredL
Round 3,653 to the nearest hundredI
Round 20 to the nearest tenH
Round 3,189 to the nearest thousandF
Round 426 to the nearest tenY
Round 1,131 to the nearest hundredE
Round 366 to the nearest tenR
0/16 letters found
Clue 5
Division facts (1-12) — the last clue
We divided the recovered map fragments equally among all the cadet teams to decode the 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
80 ÷ 8 = ?
24 ÷ 2 = ?
40 ÷ 5 = ?
30 ÷ 10 = ?
7 ÷ 1 = ?
90 ÷ 10 = ?
121 ÷ 11 = ?
3 ÷ 3 = ?
12 ÷ 3 = ?
55 ÷ 11 = ?
16 ÷ 8 = ?
Step 2 — cross out the sentence with each answer
1.The villain charted the night sky, then tracked the paths with a brass compass.
2.The villain warped the parchment map, then soared past the lookout on glider wings.
3.The villain warped the parchment map, then vanished into mist with a fog lantern.
4.The villain shifted the bay currents, then soared past the lookout on glider wings.
5.The villain charted the night sky, then zipped away using a grappling hook.
6.The villain pulled the tide high, then spied on the harbor with a pocket telescope.
7.The villain charted the night sky, then vanished into mist with a fog lantern.
8.The villain warped the parchment map, then spied on the harbor with a pocket telescope.
9.The villain summoned a gust of wind, then vanished into mist with a fog lantern.
10.The villain pulled the tide high, then zipped away using a grappling hook.
11.The villain pulled the tide high, then vanished into mist with a fog lantern.
12.The villain summoned a gust of wind, then soared past the lookout on glider wings.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Case of the Missing Compass Rose
Culprit: Finn Oakley (Tide Bending · Pocket Telescope · Left-handed writer · Spiky red hair · Salty sea breeze)
- Clue 1 (Fractions of a number): "THE VILLAIN DOES NOT CARRY A BRASS COMPASS"1/5 of 95 = 19 (T) · 2/10 of 80 = 16 (Y) · 2/3 of 18 = 12 (V) · 3/6 of 34 = 17 (C) · 2/10 of 105 = 21 (H) · 4/6 of 48 = 32 (S) · 4/8 of 26 = 13 (D) · 2/6 of 42 = 14 (R) · 2/6 of 54 = 18 (E) · 2/4 of 8 = 4 (L) · 2/3 of 39 = 26 (A) · 3/6 of 54 = 27 (I) · 3/6 of 58 = 29 (M) · 1/3 of 114 = 38 (N) · 2/5 of 5 = 2 (P) · 2/6 of 21 = 7 (O) · 1/10 of 110 = 11 (B)
- Clue 2 (Order of operations): "THE VILLAIN SIGNED THE NOTE WITH A LEFT HAND"5 × 12 - 20 = 40 (T) · 8 × 8 - 16 = 48 (I) · 12 × 3 - 20 = 16 (V) · 56 + 5 × 4 = 76 (E) · 7 × 11 - 28 = 49 (N) · 5 × 12 - 26 = 34 (W) · 2 × 10 - 9 = 11 (A) · 6 × 12 - 10 = 62 (G) · 8 × 4 - 1 = 31 (O) · 3 × 12 - 6 = 30 (F) · 3 × 10 - 12 = 18 (S) · 12 × 7 - 23 = 61 (H) · 7 × 10 - 29 = 41 (D) · 10 × 8 - 21 = 59 (L)
- Clue 3 (Multiplication facts (1-12)): "THE SNEAK FLEES FROM A SALTY SEA BREEZE"11 × 4 = 44 (T) · 11 × 10 = 110 (S) · 3 × 9 = 27 (A) · 10 × 10 = 100 (L) · 12 × 4 = 48 (E) · 1 × 11 = 11 (H) · 3 × 11 = 33 (K) · 5 × 9 = 45 (Y) · 12 × 10 = 120 (O) · 10 × 9 = 90 (F) · 4 × 7 = 28 (N) · 8 × 1 = 8 (B) · 12 × 7 = 84 (Z) · 7 × 10 = 70 (R) · 2 × 1 = 2 (M)
- Clue 4 (Rounding): "SPIKY RED HAIR WAS LEFT AT THE SCENE"Round 2,919 to the nearest hundred = 2900 (S) · Round 48 to the nearest ten = 50 (K) · Round 942 to the nearest hundred = 900 (C) · Round 234 to the nearest ten = 230 (P) · Round 8,680 to the nearest thousand = 9000 (A) · Round 657 to the nearest hundred = 700 (T) · Round 483 to the nearest hundred = 500 (W) · Round 86 to the nearest ten = 90 (D) · Round 4,274 to the nearest hundred = 4300 (N) · Round 179 to the nearest hundred = 200 (L) · Round 3,653 to the nearest hundred = 3700 (I) · Round 20 to the nearest ten = 20 (H) · Round 3,189 to the nearest thousand = 3000 (F) · Round 426 to the nearest ten = 430 (Y) · Round 1,131 to the nearest hundred = 1100 (E) · Round 366 to the nearest ten = 370 (R)
- Clue 5 (Division facts (1-12)): surviving statement (box 6) → Finn Oakley80 ÷ 8 = 10 · 24 ÷ 2 = 12 · 40 ÷ 5 = 8 · 30 ÷ 10 = 3 · 7 ÷ 1 = 7 · 90 ÷ 10 = 9 · 121 ÷ 11 = 11 · 3 ÷ 3 = 1 · 12 ÷ 3 = 4 · 55 ÷ 11 = 5 · 16 ÷ 8 = 2
About this mystery
- Grade level
- Grade 5 math
- Math topics
- Fractions of a number, Order of operations, Multiplication, Rounding, Division
- Reading level
- grades 3-4
- Theme
- The Case of the Missing Compass Rose — set in Sapphire Cove Island Academy
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects