Grade 3Reading: grades 3-4RoundingBar modelsMultiplicationFractions of a number
The Whispering Island Mystery
The legendary Golden Compass has vanished from the main cabin at Whispering Island! Without it, the young adventurers cannot navigate the deep jungle. A rogue explorer has hidden it away. Use your camp skills and solve the clues to find out who took the compass before the sun sets!
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 | Scouting Tool | Backpack Gear | Hand Trait | Headwear | Secret Foil |
|---|---|---|---|---|---|
| Hiker Mia | grappling hook | decoder ring | right handed | brown cap | banana peel |
| Iris | laser flashlight | walkie talkie | left handed | green helmet | banana peel |
| Ranger Cleo | metal detector | decoder ring | right handed | brown cap | banana peel |
| Explorer Zoe | grappling hook | waterproof map | right handed | blue bandana | banana peel |
| Camper Lily | laser flashlight | smoke bomb | right handed | brown cap | banana peel |
| Camper Sam | night vision goggles | decoder ring | left handed | green helmet | sticky honey |
| Luke | metal detector | smoke bomb | right handed | blue bandana | banana peel |
| Explorer Ben | metal detector | walkie talkie | left handed | brown cap | sticky honey |
| Cody | laser flashlight | waterproof map | right handed | green helmet | bright flash |
| Finn | night vision goggles | smoke bomb | right handed | blue bandana | banana peel |
| Lana | metal detector | walkie talkie | left handed | green helmet | bright flash |
| Ruby | pocket drone | climbing spikes | left handed | green helmet | bright flash |
| Scout Leo | laser flashlight | smoke bomb | left handed | blue bandana | banana peel |
| Ranger Jack | grappling hook | waterproof map | left handed | brown cap | bright flash |
| Kai | grappling hook | smoke bomb | right handed | blue bandana | bright flash |
| Penny | pocket drone | walkie talkie | right handed | blue bandana | banana peel |
| Skye | night vision goggles | decoder ring | right handed | blue bandana | bright flash |
| Sienna | metal detector | climbing spikes | right handed | blue bandana | banana peel |
| Otis | night vision goggles | decoder ring | left handed | green helmet | bright flash |
| Hiker Max | grappling hook | decoder ring | left handed | brown cap | sticky honey |
| Gemma | laser flashlight | waterproof map | right handed | blue bandana | sticky honey |
Clue 1
Rounding
We found a torn notebook page on the grass. It has a bar model comparing the runaway scout's trail markers to ours. Solve the bars to see what tool they left behind.
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
30
3000
7000
50
5000
7000
8000
9000
80
700
6000
40
300
7000
90
6000
7000
50
5000
6000
T
30
3000
8000
20
7000
8000
900
8000
70
9000
500
7000
T
30
8000
70
9000
500
7000
Round 31 to the nearest tenT
Round 7,420 to the nearest thousandE
Round 3,175 to the nearest thousandH
Round 7,891 to the nearest thousandA
Round 4,826 to the nearest thousandN
Round 907 to the nearest hundredW
Round 663 to the nearest hundredR
Round 49 to the nearest tenS
Round 91 to the nearest tenD
Round 8,780 to the nearest thousandK
Round 473 to the nearest hundredI
Round 22 to the nearest tenV
Round 41 to the nearest tenG
Round 6,216 to the nearest thousandO
Round 337 to the nearest hundredU
Round 67 to the nearest tenL
Round 84 to the nearest tenY
0/17 letters found
Clue 2
Bar model word problems
Our camp radar screen is a bit fuzzy from the wet jungle air. It only shows distances rounded to the nearest ten meters. Let us round the numbers to trace the target.
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
32
41
19
18
40
18
26
10
D
E
D
One group collected 15 canteen cups and another group collected 17 canteen cups. How many canteen cups in all?
draw a bar model
Answer:→R
The red team has 20 canteen cups and the blue team has 10 canteen cups. How many more canteen cups does the red team have?
draw a bar model
Answer:→N
Ranger Pete has 104 trail snacks, packed 4 to a bag. How many bags can be filled?
draw a bar model
Answer:→A
One group collected 8 pinecones and another group collected 32 pinecones. How many pinecones in all?
draw a bar model
Answer:→T
Ranger Pete has 164 trail snacks, packed 4 to a bag. How many bags can be filled?
draw a bar model
Answer:→I
One group collected 6 map pieces and another group collected 13 map pieces. How many map pieces in all?
draw a bar model
Answer:→G
Ranger Pete has 6 times as many canteen cups as a teammate. The teammate has 3 canteen cups. How many canteen cups does Ranger Pete have?
draw a bar model
Answer:→H
0/7 letters found
Clue 3
Multiplication facts (1-12)
We found piles of supply boxes stacked up in even groups. Let us multiply the rows to see how many snacks the target packed for their getaway.
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
27
132
1
63
9
30
32
121
121
1
2
60
121
72
28
40
63
1
30
30
72
81
96
40
28
40
28
40
121
1
1
30
9 × 3 =T
7 × 9 =Y
7 × 4 =N
11 × 11 =P
2 × 1 =D
5 × 12 =U
5 × 8 =A
4 × 8 =I
6 × 12 =O
1 × 1 =E
11 × 12 =H
9 × 1 =S
8 × 12 =B
9 × 9 =W
3 × 10 =L
0/15 letters found
Clue 4
Fractions of a number
The runaway dropped a bag of shiny rocks. A fraction of the rocks have arrow signs painted on them. Find the fraction to see which path they took.
Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.
W
10
8
11
23
22
16
21
9
38
19
7
35
18
4
38
39
22
8
38
9
16
21
9
16
9
23
16
4
18
8
4
19
9
7
39
1/6 of 60 =W
1/2 of 32 =N
6/10 of 15 =A
1/2 of 38 =R
1/10 of 180 =H
2/8 of 44 =F
2/10 of 195 =L
2/5 of 10 =T
2/4 of 14 =I
1/10 of 80 =E
3/6 of 42 =D
2/8 of 92 =O
2/8 of 140 =G
2/8 of 152 =B
2/6 of 66 =U
0/15 letters found
Clue 5
Fractions of a number — the last clue
We found a map of the island divided into equal areas. The runner crossed a fraction of these zones. Calculate the fraction to find their hideout.
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
5/10 of 16 = ?
2/3 of 3 = ?
1/3 of 3 = ?
4/10 of 15 = ?
5/10 of 10 = ?
1/10 of 30 = ?
1/6 of 24 = ?
2/6 of 36 = ?
9/10 of 10 = ?
3/6 of 22 = ?
2/8 of 40 = ?
Step 2 — cross out the sentence with each answer
1.The villain searches the sandy beach with a metal detector, then escapes up the cliff with climbing spikes.
2.The villain swings across the river using a grappling hook, then crosses the swamp using a waterproof map.
3.The villain sneaks through the dark with night vision goggles, then calls for backup on a walkie talkie.
4.The villain searches the sandy beach with a metal detector, then crosses the swamp using a waterproof map.
5.The villain swings across the river using a grappling hook, then calls for backup on a walkie talkie.
6.The villain sneaks through the dark with night vision goggles, then escapes up the cliff with climbing spikes.
7.The villain sneaks through the dark with night vision goggles, then vanishes into the trees with a smoke bomb.
8.The villain searches the sandy beach with a metal detector, then vanishes into the trees with a smoke bomb.
9.The villain scouts the area using a pocket drone, then calls for backup on a walkie talkie.
10.The villain lights up the dark cave with a laser flashlight, then crosses the swamp using a waterproof map.
11.The villain lights up the dark cave with a laser flashlight, then unlocks the secret box with a decoder ring.
12.The villain lights up the dark cave with a laser flashlight, then vanishes into the trees with a smoke bomb.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Whispering Island Mystery
Culprit: Finn (night vision goggles · smoke bomb · right handed · blue bandana · banana peel)
- Clue 1 (Rounding): "THE SNEAKY ROGUE DOES NOT HAVE A WALKIE TALKIE"Round 31 to the nearest ten = 30 (T) · Round 7,420 to the nearest thousand = 7000 (E) · Round 3,175 to the nearest thousand = 3000 (H) · Round 7,891 to the nearest thousand = 8000 (A) · Round 4,826 to the nearest thousand = 5000 (N) · Round 907 to the nearest hundred = 900 (W) · Round 663 to the nearest hundred = 700 (R) · Round 49 to the nearest ten = 50 (S) · Round 91 to the nearest ten = 90 (D) · Round 8,780 to the nearest thousand = 9000 (K) · Round 473 to the nearest hundred = 500 (I) · Round 22 to the nearest ten = 20 (V) · Round 41 to the nearest ten = 40 (G) · Round 6,216 to the nearest thousand = 6000 (O) · Round 337 to the nearest hundred = 300 (U) · Round 67 to the nearest ten = 70 (L) · Round 84 to the nearest ten = 80 (Y)
- Clue 2 (Bar model word problems): "RIGHT HANDED"One group collected 15 canteen cups and another group collected 17 canteen cups. How many canteen cups in all? = 32 (R) · The red team has 20 canteen cups and the blue team has 10 canteen cups. How many more canteen cups does the red team have? = 10 (N) · Ranger Pete has 104 trail snacks, packed 4 to a bag. How many bags can be filled? = 26 (A) · One group collected 8 pinecones and another group collected 32 pinecones. How many pinecones in all? = 40 (T) · Ranger Pete has 164 trail snacks, packed 4 to a bag. How many bags can be filled? = 41 (I) · One group collected 6 map pieces and another group collected 13 map pieces. How many map pieces in all? = 19 (G) · Ranger Pete has 6 times as many canteen cups as a teammate. The teammate has 3 canteen cups. How many canteen cups does Ranger Pete have? = 18 (H)
- Clue 3 (Multiplication facts (1-12)): "THEY SLIPPED UPON A YELLOW BANANA PEEL"9 × 3 = 27 (T) · 7 × 9 = 63 (Y) · 7 × 4 = 28 (N) · 11 × 11 = 121 (P) · 2 × 1 = 2 (D) · 5 × 12 = 60 (U) · 5 × 8 = 40 (A) · 4 × 8 = 32 (I) · 6 × 12 = 72 (O) · 1 × 1 = 1 (E) · 11 × 12 = 132 (H) · 9 × 1 = 9 (S) · 8 × 12 = 96 (B) · 9 × 9 = 81 (W) · 3 × 10 = 30 (L)
- Clue 4 (Fractions of a number): "WE FOUND A BRIGHT BLUE BANDANA ON THE TRAIL"1/6 of 60 = 10 (W) · 1/2 of 32 = 16 (N) · 6/10 of 15 = 9 (A) · 1/2 of 38 = 19 (R) · 1/10 of 180 = 18 (H) · 2/8 of 44 = 11 (F) · 2/10 of 195 = 39 (L) · 2/5 of 10 = 4 (T) · 2/4 of 14 = 7 (I) · 1/10 of 80 = 8 (E) · 3/6 of 42 = 21 (D) · 2/8 of 92 = 23 (O) · 2/8 of 140 = 35 (G) · 2/8 of 152 = 38 (B) · 2/6 of 66 = 22 (U)
- Clue 5 (Fractions of a number): surviving statement (box 7) → Finn5/10 of 16 = 8 · 2/3 of 3 = 2 · 1/3 of 3 = 1 · 4/10 of 15 = 6 · 5/10 of 10 = 5 · 1/10 of 30 = 3 · 1/6 of 24 = 4 · 2/6 of 36 = 12 · 9/10 of 10 = 9 · 3/6 of 22 = 11 · 2/8 of 40 = 10
About this mystery
- Grade level
- Grade 3 math
- Math topics
- Rounding, Bar models, Multiplication, Fractions of a number
- Reading level
- grades 3-4
- Theme
- The Whispering Island Mystery — set in Whispering Island Adventure Camp
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects