Grade 4Reading: grades 3-4RoundingAdditionSubtractionMultiplicationDivision
The Mystery of the Crystal Compass
Oh no! Someone snuck into the Temple of Bananas and snatched the ancient Crystal Compass! The Chief Archeologist needs the Treehouse Explorer Club to follow the clues, use their math skills, and unmask the Rogue Explorer before they escape the jungle!
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 | Camp Mascot | Compass Pocket | Helmet Style | Favorite Snack Distraction |
|---|---|---|---|---|---|
| Clara | Machete Tool | Tiny Tree Frog | Left Pocket Compass | Bright Red Bandana | Crunchy Banana Chips |
| Eva | Climbing Claws | Squeaky Squirrel | Right Pocket Compass | Bright Red Bandana | Crunchy Banana Chips |
| Val | Spy Glass | Baby Monkey | Right Pocket Compass | Feathered Safari Hat | Salty Pretzel Twists |
| Noah | Spy Glass | Green Iguana | Right Pocket Compass | Pith Helmet | Crunchy Banana Chips |
| Maya | Spy Glass | Squeaky Squirrel | Right Pocket Compass | Feathered Safari Hat | Sour Apple Gummies |
| Grace | Machete Tool | Baby Monkey | Left Pocket Compass | Bright Red Bandana | Sour Apple Gummies |
| Quinn | Climbing Claws | Baby Monkey | Right Pocket Compass | Pith Helmet | Crunchy Banana Chips |
| Finn | Laser Flashlight | Green Iguana | Left Pocket Compass | Bright Red Bandana | Crunchy Banana Chips |
| Barnaby | Grappling Hook | Trained Parrot | Left Pocket Compass | Pith Helmet | Crunchy Banana Chips |
| Sam | Laser Flashlight | Baby Monkey | Left Pocket Compass | Pith Helmet | Sour Apple Gummies |
| Daniel | Climbing Claws | Tiny Tree Frog | Right Pocket Compass | Pith Helmet | Crunchy Banana Chips |
| Ulysses | Spy Glass | Squeaky Squirrel | Left Pocket Compass | Bright Red Bandana | Salty Pretzel Twists |
| Zoe | Laser Flashlight | Tiny Tree Frog | Left Pocket Compass | Pith Helmet | Salty Pretzel Twists |
| Leo | Climbing Claws | Green Iguana | Right Pocket Compass | Bright Red Bandana | Salty Pretzel Twists |
| Hudson | Grappling Hook | Green Iguana | Left Pocket Compass | Bright Red Bandana | Crunchy Banana Chips |
| Olivia | Grappling Hook | Baby Monkey | Left Pocket Compass | Bright Red Bandana | Crunchy Banana Chips |
| Tessa | Spy Glass | Trained Parrot | Left Pocket Compass | Bright Red Bandana | Crunchy Banana Chips |
| Amelia | Machete Tool | Squeaky Squirrel | Left Pocket Compass | Feathered Safari Hat | Crunchy Banana Chips |
| Wyatt | Grappling Hook | Tiny Tree Frog | Left Pocket Compass | Bright Red Bandana | Crunchy Banana Chips |
| Isabella | Grappling Hook | Baby Monkey | Left Pocket Compass | Pith Helmet | Sour Apple Gummies |
| Parker | Laser Flashlight | Baby Monkey | Left Pocket Compass | Bright Red Bandana | Salty Pretzel Twists |
Clue 1
Rounding
We found an old walkie-talkie dropped in the mud! The screen is cracked, so the distance meter only shows the nearest rounded ten miles. We must round the numbers to find the signal!
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
300
200
9000
50
370
900
900
2000
370
70
2900
3000
9000
290
70
3000
T
300
200
2000
50
9000
2000
1100
7000
9000
9000
70
370
1100
130
2000
70
2000
Round 290 to the nearest hundredT
Round 6,773 to the nearest thousandR
Round 130 to the nearest tenU
Round 2,752 to the nearest thousandO
Round 48 to the nearest tenV
Round 2,911 to the nearest hundredD
Round 290 to the nearest tenS
Round 193 to the nearest hundredH
Round 8,629 to the nearest thousandE
Round 373 to the nearest tenI
Round 851 to the nearest hundredL
Round 66 to the nearest tenN
Round 1,095 to the nearest hundredG
Round 1,912 to the nearest thousandA
0/14 letters found
Clue 2
Addition
We found the rogue's camp footprint! To find out how heavy they were, we need to add up the weights of all the supply crates left behind in the dirt.
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
9205
2862
7805
T
9205
2862
4171
7805
3615
5329
2835
5075
5075
4171
7805
6988
2835
2760
7805
3615
T
9205
8068
9028
5329
7491
7805
T
9205
5329
9028
9494
8068
2835
6988
6988
4540 + 4665 =T
1168 + 2447 =F
3312 + 4179 =K
3857 + 4211 =P
4317 + 4711 =O
2252 + 2823 =R
1554 + 1308 =H
1569 + 1266 =A
6248 + 3246 =M
5357 + 2448 =E
4105 + 2883 =S
855 + 1905 =L
2935 + 2394 =C
1944 + 2227 =I
0/14 letters found
Clue 3
Subtraction
The thief stole some fuel from our jeep! We need to subtract the remaining fuel from the starting amount to see how far they could run.
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
6150
2898
8347
8550
5409
8945
4219
7180
7180
8347
5409
8692
8945
8731
8445
8692
2898
8550
1128
3317
8445
3317
8445
3317
8692
2898
7383
7180
7914
6336 - 186 =T
9049 - 499 =Y
7795 - 412 =I
7882 - 702 =P
12635 - 3943 =C
5352 - 1133 =O
10885 - 1940 =R
9524 - 1177 =E
10435 - 2521 =S
12781 - 4336 =N
9766 - 4357 =D
5923 - 3025 =H
3943 - 626 =A
2075 - 947 =B
9374 - 643 =U
0/15 letters found
Clue 4
Multiplication facts (1-12)
The rogue ran across the temple floor! They stepped on ancient tiles laid out in equal rows and columns. Multiply the rows to count how many tiles they stepped on.
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
50
48
100
40
32
7
108
70
72
120
11
6
15
72
50
7
70
108
32
7
108
32
108
2 × 5 =W
3 × 5 =T
2 × 3 =H
9 × 8 =R
10 × 4 =U
10 × 10 =O
12 × 9 =A
8 × 4 =N
1 × 7 =D
10 × 12 =I
12 × 4 =F
10 × 5 =E
10 × 7 =B
1 × 11 =G
0/14 letters found
Clue 5
Division facts (1-12) — the last clue
To escape across the river, the rogue threw cargo off their raft to keep it light. We can divide the total weight by the number of boxes to see how heavy each box was.
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
18 ÷ 6 = ?
72 ÷ 9 = ?
10 ÷ 5 = ?
40 ÷ 10 = ?
15 ÷ 3 = ?
88 ÷ 8 = ?
8 ÷ 8 = ?
18 ÷ 3 = ?
50 ÷ 5 = ?
84 ÷ 12 = ?
81 ÷ 9 = ?
Step 2 — cross out the sentence with each answer
1.The villain climbed up the tall stone wall, then held the scaly iguana.
2.The villain cleared the thick vines with a tool, then let the tree frog hop along.
3.The villain climbed up the tall stone wall, then fed the hungry parrot.
4.The villain scrambled up the mud slide, then held the scaly iguana.
5.The villain cleared the thick vines with a tool, then shared a nut with the squirrel.
6.The villain cleared the thick vines with a tool, then gave a banana to the monkey.
7.The villain swung across the canyon using a rope, then held the scaly iguana.
8.The villain swung across the canyon using a rope, then gave a banana to the monkey.
9.The villain cleared the thick vines with a tool, then held the scaly iguana.
10.The villain climbed up the tall stone wall, then let the tree frog hop along.
11.The villain climbed up the tall stone wall, then gave a banana to the monkey.
12.The villain swung across the canyon using a rope, then let the tree frog hop along.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Mystery of the Crystal Compass
Culprit: Wyatt (Grappling Hook · Tiny Tree Frog · Left Pocket Compass · Bright Red Bandana · Crunchy Banana Chips)
- Clue 1 (Rounding): "THE VILLAIN DOES NOT HAVE A GREEN IGUANA"Round 290 to the nearest hundred = 300 (T) · Round 6,773 to the nearest thousand = 7000 (R) · Round 130 to the nearest ten = 130 (U) · Round 2,752 to the nearest thousand = 3000 (O) · Round 48 to the nearest ten = 50 (V) · Round 2,911 to the nearest hundred = 2900 (D) · Round 290 to the nearest ten = 290 (S) · Round 193 to the nearest hundred = 200 (H) · Round 8,629 to the nearest thousand = 9000 (E) · Round 373 to the nearest ten = 370 (I) · Round 851 to the nearest hundred = 900 (L) · Round 66 to the nearest ten = 70 (N) · Round 1,095 to the nearest hundred = 1100 (G) · Round 1,912 to the nearest thousand = 2000 (A)
- Clue 2 (Addition): "THE THIEF CARRIES A LEFT POCKET COMPASS"4540 + 4665 = 9205 (T) · 1168 + 2447 = 3615 (F) · 3312 + 4179 = 7491 (K) · 3857 + 4211 = 8068 (P) · 4317 + 4711 = 9028 (O) · 2252 + 2823 = 5075 (R) · 1554 + 1308 = 2862 (H) · 1569 + 1266 = 2835 (A) · 6248 + 3246 = 9494 (M) · 5357 + 2448 = 7805 (E) · 4105 + 2883 = 6988 (S) · 855 + 1905 = 2760 (L) · 2935 + 2394 = 5329 (C) · 1944 + 2227 = 4171 (I)
- Clue 3 (Subtraction): "THEY DROPPED CRUNCHY BANANA CHIPS"6336 - 186 = 6150 (T) · 9049 - 499 = 8550 (Y) · 7795 - 412 = 7383 (I) · 7882 - 702 = 7180 (P) · 12635 - 3943 = 8692 (C) · 5352 - 1133 = 4219 (O) · 10885 - 1940 = 8945 (R) · 9524 - 1177 = 8347 (E) · 10435 - 2521 = 7914 (S) · 12781 - 4336 = 8445 (N) · 9766 - 4357 = 5409 (D) · 5923 - 3025 = 2898 (H) · 3943 - 626 = 3317 (A) · 2075 - 947 = 1128 (B) · 9374 - 643 = 8731 (U)
- Clue 4 (Multiplication facts (1-12)): "WE FOUND A BRIGHT RED BANDANA"2 × 5 = 10 (W) · 3 × 5 = 15 (T) · 2 × 3 = 6 (H) · 9 × 8 = 72 (R) · 10 × 4 = 40 (U) · 10 × 10 = 100 (O) · 12 × 9 = 108 (A) · 8 × 4 = 32 (N) · 1 × 7 = 7 (D) · 10 × 12 = 120 (I) · 12 × 4 = 48 (F) · 10 × 5 = 50 (E) · 10 × 7 = 70 (B) · 1 × 11 = 11 (G)
- Clue 5 (Division facts (1-12)): surviving statement (box 12) → Wyatt18 ÷ 6 = 3 · 72 ÷ 9 = 8 · 10 ÷ 5 = 2 · 40 ÷ 10 = 4 · 15 ÷ 3 = 5 · 88 ÷ 8 = 11 · 8 ÷ 8 = 1 · 18 ÷ 3 = 6 · 50 ÷ 5 = 10 · 84 ÷ 12 = 7 · 81 ÷ 9 = 9
About this mystery
- Grade level
- Grade 4 math
- Math topics
- Rounding, Addition, Subtraction, Multiplication, Division
- Reading level
- grades 3-4
- Theme
- The Mystery of the Crystal Compass — set in The Mossy Vine Jungle and the Temple of Bananas
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects