Grade 4Reading: grades 3-4RoundingBar modelsAdditionSubtractionDivision
The Sapphire Cavern Mystery
A sneaky intruder snuck into the Sapphire Cavern base camp and snatched the master map! Work through the clues to uncover 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 | Main Tool | Gadget | Dominant Hand | Hair Color | Fear |
|---|---|---|---|---|---|
| Jasper Cole | Rope Launcher | Hookshots | Right-Handed | Red Hair | Loud Whistles |
| Cora Sterling | Glider Wings | Pocket Compass | Right-Handed | Red Hair | Loud Whistles |
| Piper Reed | Rope Launcher | Night Goggles | Left-Handed | Red Hair | Loud Whistles |
| Wyatt Briggs | Torch Blaster | Night Goggles | Right-Handed | Black Hair | Loud Whistles |
| Drake Holloway | Smoke Bombs | Pocket Compass | Right-Handed | Red Hair | Cold Sprays |
| Uriah Knox | Climbing Claws | Hookshots | Left-Handed | Red Hair | Bright Flashes |
| Leo Maxwell | Smoke Bombs | Pocket Compass | Right-Handed | Red Hair | Loud Whistles |
| Sam Silas | Glider Wings | Hookshots | Right-Handed | Blonde Hair | Loud Whistles |
| Felix OConnor | Glider Wings | Night Goggles | Right-Handed | Red Hair | Loud Whistles |
| Owen Mercer | Glider Wings | Magnetic Boots | Right-Handed | Red Hair | Loud Whistles |
| Quinn Harper | Climbing Claws | Magnetic Boots | Left-Handed | Red Hair | Cold Sprays |
| Barnaby Finch | Torch Blaster | Night Goggles | Left-Handed | Black Hair | Bright Flashes |
| Tessa Vale | Smoke Bombs | Hookshots | Left-Handed | Red Hair | Bright Flashes |
| Amelia Vance | Glider Wings | Hookshots | Right-Handed | Red Hair | Loud Whistles |
| Gideon Drake | Glider Wings | Hookshots | Left-Handed | Red Hair | Cold Sprays |
| Ruby Stone | Torch Blaster | Night Goggles | Right-Handed | Red Hair | Bright Flashes |
| Elena Cruz | Smoke Bombs | Magnetic Boots | Left-Handed | Red Hair | Bright Flashes |
| Milo Vance | Climbing Claws | Night Goggles | Left-Handed | Black Hair | Loud Whistles |
| Nia Brooks | Climbing Claws | Pocket Compass | Left-Handed | Blonde Hair | Bright Flashes |
| Violet Hayes | Rope Launcher | Night Goggles | Left-Handed | Black Hair | Cold Sprays |
| Zane Cross | Glider Wings | Pocket Compass | Right-Handed | Black Hair | Loud Whistles |
Clue 1
Rounding
We compared the gear weights using bar models on our map tablet to cross off one useless gadget.
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
7000
500
3000
290
2900
430
200
3000
290
200
430
200
2000
4300
T
7000
2300
1100
3000
500
4300
4300
70
1100
500
4300
T
7000
1100
Round 6,952 to the nearest thousandT
Round 1,524 to the nearest thousandN
Round 238 to the nearest hundredD
Round 2,261 to the nearest hundredU
Round 73 to the nearest tenK
Round 4,257 to the nearest hundredO
Round 2,931 to the nearest hundredA
Round 293 to the nearest tenR
Round 489 to the nearest hundredH
Round 3,331 to the nearest thousandE
Round 1,064 to the nearest hundredS
Round 428 to the nearest tenI
0/12 letters found
Clue 2
Bar model word problems
The cavern scanner only shows rounded power numbers so we rounded each signal to spot a clue.
Draw a bar model to solve each word problem. Its answer reveals a letter — write the letters in the boxes to fill in the missing word.
Awitnesssawthevillainwas .
R
14
47
21
10
27
10
131
91
D
E
D
Trail scout has 2 times as many compass as a teammate. The teammate has 7 compass. How many compass does trail scout have?
draw a bar model
Answer:→R
Trail scout has 2 times as many gemstone as a teammate. The teammate has 5 gemstone. How many gemstone does trail scout have?
draw a bar model
Answer:→H
Trail scout has 182 rope coil, packed 2 to a bag. How many bags can be filled?
draw a bar model
Answer:→N
There were 59 compass in all. 12 compass were used. How many compass are left?
draw a bar model
Answer:→I
There were 164 canteen in all. 33 canteen were used. How many canteen are left?
draw a bar model
Answer:→A
Trail scout has 7 times as many canteen as a teammate. The teammate has 3 canteen. How many canteen does trail scout have?
draw a bar model
Answer:→G
Trail scout used 1/3 of the gemstone on the first day. The other 18 gemstone were used the next day. How many gemstone were there in all?
draw a bar model
Answer:→T
0/7 letters found
Clue 3
Addition
We added up all the lost supply counts found along the wet tunnel to find another lead.
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
7689
9399
2136
5942
7269
7854
9314
2136
5942
8024
2136
7269
5942
2136
9314
7807
7786
3884
9314
3342
9399
7854
5495
T
7689
7807
2136
5495
4625 + 3064 =T
2033 + 3909 =R
2102 + 1240 =W
1485 + 2399 =U
3394 + 2101 =S
1015 + 1121 =E
3889 + 3918 =L
3836 + 4018 =I
4149 + 3120 =A
3106 + 6208 =D
3639 + 4147 =O
4407 + 4992 =H
4468 + 3556 =F
0/13 letters found
Clue 4
Subtraction
We subtracted the stolen packs from our starting supplies to discover what hair clue remained.
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
7979
7575
6143
7768
8612
3621
2580
6143
7768
3386
6143
4791
T
7979
7768
6143
2580
7575
8612
3621
7768
8612
T
7979
6663
4958
6143
5020
6143
9958 - 1979 =T
4889 - 1503 =L
9231 - 4211 =N
10776 - 4113 =S
3149 - 569 =D
7205 - 2414 =F
11284 - 3516 =R
7203 - 3582 =I
9067 - 2924 =E
12362 - 4787 =H
12047 - 3435 =A
7828 - 2870 =C
0/12 letters found
Clue 5
Division facts (1-12) — the last clue
We divided the final evidence cards equally among our scouts to catch the intruder.
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
6 ÷ 6 = ?
24 ÷ 3 = ?
66 ÷ 11 = ?
84 ÷ 7 = ?
32 ÷ 8 = ?
10 ÷ 1 = ?
3 ÷ 1 = ?
21 ÷ 3 = ?
54 ÷ 6 = ?
99 ÷ 9 = ?
22 ÷ 11 = ?
Step 2 — cross out the sentence with each answer
1.The villain soared in with glider wings, then navigated tunnels with a pocket compass.
2.The villain created a distraction with smoke bombs, then spotted targets using night goggles.
3.The villain scaled the wall with climbing claws, then navigated tunnels with a pocket compass.
4.The villain scaled the wall with climbing claws, then walked on metal beams with magnetic boots.
5.The villain created a distraction with smoke bombs, then navigated tunnels with a pocket compass.
6.The villain soared in with glider wings, then spotted targets using night goggles.
7.The villain swung over gaps with a rope launcher, then spotted targets using night goggles.
8.The villain soared in with glider wings, then walked on metal beams with magnetic boots.
9.The villain soared in with glider wings, then zipped upward using a hookshot.
10.The villain scaled the wall with climbing claws, then spotted targets using night goggles.
11.The villain scaled the wall with climbing claws, then zipped upward using a hookshot.
12.The villain swung over gaps with a rope launcher, then navigated tunnels with a pocket compass.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Sapphire Cavern Mystery
Culprit: Leo Maxwell (Smoke Bombs · Pocket Compass · Right-Handed · Red Hair · Loud Whistles)
- Clue 1 (Rounding): "THE RAIDER DID NOT USE HOOKSHOTS"Round 6,952 to the nearest thousand = 7000 (T) · Round 1,524 to the nearest thousand = 2000 (N) · Round 238 to the nearest hundred = 200 (D) · Round 2,261 to the nearest hundred = 2300 (U) · Round 73 to the nearest ten = 70 (K) · Round 4,257 to the nearest hundred = 4300 (O) · Round 2,931 to the nearest hundred = 2900 (A) · Round 293 to the nearest ten = 290 (R) · Round 489 to the nearest hundred = 500 (H) · Round 3,331 to the nearest thousand = 3000 (E) · Round 1,064 to the nearest hundred = 1100 (S) · Round 428 to the nearest ten = 430 (I)
- Clue 2 (Bar model word problems): "RIGHT HANDED"Trail scout has 2 times as many compass as a teammate. The teammate has 7 compass. How many compass does trail scout have? = 14 (R) · Trail scout has 2 times as many gemstone as a teammate. The teammate has 5 gemstone. How many gemstone does trail scout have? = 10 (H) · Trail scout has 182 rope coil, packed 2 to a bag. How many bags can be filled? = 91 (N) · There were 59 compass in all. 12 compass were used. How many compass are left? = 47 (I) · There were 164 canteen in all. 33 canteen were used. How many canteen are left? = 131 (A) · Trail scout has 7 times as many canteen as a teammate. The teammate has 3 canteen. How many canteen does trail scout have? = 21 (G) · Trail scout used 1/3 of the gemstone on the first day. The other 18 gemstone were used the next day. How many gemstone were there in all? = 27 (T)
- Clue 3 (Addition): "THE RAIDER FEARED LOUD WHISTLES"4625 + 3064 = 7689 (T) · 2033 + 3909 = 5942 (R) · 2102 + 1240 = 3342 (W) · 1485 + 2399 = 3884 (U) · 3394 + 2101 = 5495 (S) · 1015 + 1121 = 2136 (E) · 3889 + 3918 = 7807 (L) · 3836 + 4018 = 7854 (I) · 4149 + 3120 = 7269 (A) · 3106 + 6208 = 9314 (D) · 3639 + 4147 = 7786 (O) · 4407 + 4992 = 9399 (H) · 4468 + 3556 = 8024 (F)
- Clue 4 (Subtraction): "THE RAIDER LEFT RED HAIR AT SCENE"9958 - 1979 = 7979 (T) · 4889 - 1503 = 3386 (L) · 9231 - 4211 = 5020 (N) · 10776 - 4113 = 6663 (S) · 3149 - 569 = 2580 (D) · 7205 - 2414 = 4791 (F) · 11284 - 3516 = 7768 (R) · 7203 - 3582 = 3621 (I) · 9067 - 2924 = 6143 (E) · 12362 - 4787 = 7575 (H) · 12047 - 3435 = 8612 (A) · 7828 - 2870 = 4958 (C)
- Clue 5 (Division facts (1-12)): surviving statement (box 5) → Leo Maxwell6 ÷ 6 = 1 · 24 ÷ 3 = 8 · 66 ÷ 11 = 6 · 84 ÷ 7 = 12 · 32 ÷ 8 = 4 · 10 ÷ 1 = 10 · 3 ÷ 1 = 3 · 21 ÷ 3 = 7 · 54 ÷ 6 = 9 · 99 ÷ 9 = 11 · 22 ÷ 11 = 2
About this mystery
- Grade level
- Grade 4 math
- Math topics
- Rounding, Bar models, Addition, Subtraction, Division
- Reading level
- grades 3-4
- Theme
- The Sapphire Cavern Mystery — set in Sapphire Cavern
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects