Grade 3Reading: grades 3-4RoundingAdditionSubtractionMultiplicationDivision

The Lost Idol of Isla Oro

A priceless golden monkey statue has vanished from the Jungle Museum camp! A sneaky rogue explorer took it. We must follow the trail, solve the puzzles, and find the culprit.

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	Adventure Gear	Special Map	Flashlight Hand	Bandana Color	Fear
Dora	Leather Whip	Cave Map	Right Handed Flashlight	Red Bandana	Spiders
Skip	Leather Whip	Cave Map	Right Handed Flashlight	Green Bandana	Heights
Sam	Leather Whip	Star Map	Left Handed Flashlight	Green Bandana	Loud Noises
Zoe	Golden Compass	Swamp Map	Left Handed Flashlight	Green Bandana	Spiders
Nathan	Climbing Rope	Cave Map	Left Handed Flashlight	Blue Bandana	Spiders
Lara	Pocket Binoculars	Volcano Map	Right Handed Flashlight	Blue Bandana	Heights
Maya	Steel Machete	Star Map	Left Handed Flashlight	Green Bandana	Loud Noises
Penny	Climbing Rope	Cave Map	Left Handed Flashlight	Blue Bandana	Heights
Rusty	Climbing Rope	Cave Map	Left Handed Flashlight	Red Bandana	Loud Noises
Will	Golden Compass	Cave Map	Left Handed Flashlight	Green Bandana	Spiders
Marcus	Climbing Rope	Temple Map	Right Handed Flashlight	Red Bandana	Loud Noises
Abigail	Steel Machete	Volcano Map	Left Handed Flashlight	Green Bandana	Heights
Sully	Golden Compass	Cave Map	Right Handed Flashlight	Red Bandana	Loud Noises
Finn	Leather Whip	Volcano Map	Left Handed Flashlight	Red Bandana	Spiders
Jack	Golden Compass	Swamp Map	Right Handed Flashlight	Red Bandana	Loud Noises
Leo	Steel Machete	Swamp Map	Right Handed Flashlight	Red Bandana	Spiders
Indiana	Golden Compass	Temple Map	Right Handed Flashlight	Green Bandana	Spiders
Ben	Pocket Binoculars	Cave Map	Right Handed Flashlight	Red Bandana	Spiders
Riley	Golden Compass	Cave Map	Right Handed Flashlight	Red Bandana	Spiders
Diego	Leather Whip	Star Map	Right Handed Flashlight	Red Bandana	Spiders
Gemma	Pocket Binoculars	Volcano Map	Right Handed Flashlight	Green Bandana	Spiders

Clue 1

Rounding

We found a broken digital GPS tracker on the muddy trail. Its screen is cracked, so it only shows rounded distances to the nearest ten yards. Round the distance to find where the thief dropped their first clue.

Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.

500

800

5000

9000

500

7000

700

500

5000

3000

6000

3000

Round 483 to the nearest hundredT

Round 4,990 to the nearest thousandU

Round 5,703 to the nearest thousandM

Round 726 to the nearest hundredO

Round 81 to the nearest tenR

Round 36 to the nearest tenS

Round 64 to the nearest tenN

Round 8,853 to the nearest thousandL

Round 7,202 to the nearest thousandD

Round 31 to the nearest tenW

Round 92 to the nearest tenP

Round 47 to the nearest tenE

Round 770 to the nearest hundredC

Round 22 to the nearest tenI

Round 74 to the nearest tenH

Round 2,775 to the nearest thousandA

0/16 letters found

Clue 2

Addition

A friendly monkey helped us collect torn pieces of a notebook. Let us add up the total number of paper scraps we found scattered under the banana trees.

Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.

213

347

459

373

845

635

347

213

902

459

708

526

902

454

459

726

721

902

382

400

982

721

213

347

459

400

845

635

347

213

347

726

708

526

75 + 138 =T

120 + 253 =L

257 + 202 =E

171 + 229 =R

213 + 241 =B

306 + 539 =I

371 + 337 =N

459 + 267 =A

114 + 268 =F

545 + 357 =S

333 + 388 =M

200 + 435 =G

254 + 272 =D

539 + 443 =O

126 + 221 =H

0/15 letters found

Clue 3

Subtraction

The thief dropped their heavy supply pack to run faster. If we subtract the ruined supplies from the total pack weight, we can figure out what they kept.

Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.

582

382

373

287

182

558

248

558

164

558

287

558

841

582

373

182

504

373

685

248

710

558

582

685

248

287

504

784

685

266

373

182

731 - 149 =T

766 - 384 =H

430 - 57 =E

369 - 187 =R

343 - 179 =W

623 - 119 =S

910 - 69 =F

686 - 399 =Y

876 - 318 =A

622 - 356 =D

693 - 8 =I

859 - 149 =G

645 - 397 =N

960 - 176 =P

0/14 letters found

Clue 4

Multiplication facts (1-12)

We reached a wall of ancient stone tiles. The tiles are arranged in neat rows and columns. Multiply the rows by the columns to unlock the hidden compartment.

Solve each problem to learn its letter. Then write that letter in every box that shows the same number, and read the secret clue.

120

5 × 5 =W

11 × 1 =E

2 × 4 =D

10 × 7 =R

7 × 7 =I

7 × 11 =U

5 × 3 =G

6 × 3 =A

10 × 9 =T

1 × 2 =C

9 × 7 =O

7 × 2 =N

5 × 1 =B

10 × 12 =F

8 × 12 =H

0/15 letters found

Clue 5

Division facts (1-12) — the last clue

We found a box of old explorer coins. If we share them equally among our team members, the leftover coins will reveal the final secret.

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 = ?

9 ÷ 3 = ?

70 ÷ 10 = ?

9 ÷ 1 = ?

36 ÷ 6 = ?

48 ÷ 12 = ?

5 ÷ 1 = ?

144 ÷ 12 = ?

77 ÷ 7 = ?

24 ÷ 3 = ?

18 ÷ 9 = ?

Step 2 — cross out the sentence with each answer

1.The villain checked the golden compass, then plotted a path on the cave map.

2.The villain tied a knot in the climbing rope, then plotted a path on the cave map.

3.The villain swung across the gap with the leather whip, then unrolled the star map.

4.The villain slashed vines with the steel machete, then plotted a path on the cave map.

5.The villain tied a knot in the climbing rope, then unrolled the star map.

6.The villain slashed vines with the steel machete, then drew a route on the temple map.

7.The villain swung across the gap with the leather whip, then plotted a path on the cave map.

8.The villain tied a knot in the climbing rope, then checked coordinates on the swamp map.

9.The villain checked the golden compass, then marked a trail on the volcano map.

10.The villain scanned the path with the pocket binoculars, then plotted a path on the cave map.

11.The villain tied a knot in the climbing rope, then drew a route on the temple map.

12.The villain scanned the path with the pocket binoculars, then unrolled the star map.

Solve it

Name the culprit

Choose the one suspect left standing.

Answer Key — The Lost Idol of Isla Oro

Culprit: Ben (Pocket Binoculars · Cave Map · Right Handed Flashlight · Red Bandana · Spiders)

Clue 1 (Rounding): "THE CULPRIT DOES NOT USE A SWAMP MAP"
Round 483 to the nearest hundred = 500 (T) · Round 4,990 to the nearest thousand = 5000 (U) · Round 5,703 to the nearest thousand = 6000 (M) · Round 726 to the nearest hundred = 700 (O) · Round 81 to the nearest ten = 80 (R) · Round 36 to the nearest ten = 40 (S) · Round 64 to the nearest ten = 60 (N) · Round 8,853 to the nearest thousand = 9000 (L) · Round 7,202 to the nearest thousand = 7000 (D) · Round 31 to the nearest ten = 30 (W) · Round 92 to the nearest ten = 90 (P) · Round 47 to the nearest ten = 50 (E) · Round 770 to the nearest hundred = 800 (C) · Round 22 to the nearest ten = 20 (I) · Round 74 to the nearest ten = 70 (H) · Round 2,775 to the nearest thousand = 3000 (A)
Clue 2 (Addition): "THE LIGHT SENDS BEAMS FROM THE RIGHT HAND"
75 + 138 = 213 (T) · 120 + 253 = 373 (L) · 257 + 202 = 459 (E) · 171 + 229 = 400 (R) · 213 + 241 = 454 (B) · 306 + 539 = 845 (I) · 371 + 337 = 708 (N) · 459 + 267 = 726 (A) · 114 + 268 = 382 (F) · 545 + 357 = 902 (S) · 333 + 388 = 721 (M) · 200 + 435 = 635 (G) · 254 + 272 = 526 (D) · 539 + 443 = 982 (O) · 126 + 221 = 347 (H)
Clue 3 (Subtraction): "THEY RAN AWAY AFTER SEEING A TINY SPIDER"
731 - 149 = 582 (T) · 766 - 384 = 382 (H) · 430 - 57 = 373 (E) · 369 - 187 = 182 (R) · 343 - 179 = 164 (W) · 623 - 119 = 504 (S) · 910 - 69 = 841 (F) · 686 - 399 = 287 (Y) · 876 - 318 = 558 (A) · 622 - 356 = 266 (D) · 693 - 8 = 685 (I) · 859 - 149 = 710 (G) · 645 - 397 = 248 (N) · 960 - 176 = 784 (P)
Clue 4 (Multiplication facts (1-12)): "WE FOUND A BRIGHT RED THREAD ON A BRANCH"
5 × 5 = 25 (W) · 11 × 1 = 11 (E) · 2 × 4 = 8 (D) · 10 × 7 = 70 (R) · 7 × 7 = 49 (I) · 7 × 11 = 77 (U) · 5 × 3 = 15 (G) · 6 × 3 = 18 (A) · 10 × 9 = 90 (T) · 1 × 2 = 2 (C) · 9 × 7 = 63 (O) · 7 × 2 = 14 (N) · 5 × 1 = 5 (B) · 10 × 12 = 120 (F) · 8 × 12 = 96 (H)
Clue 5 (Division facts (1-12)): surviving statement (box 10) → Ben
6 ÷ 6 = 1 · 9 ÷ 3 = 3 · 70 ÷ 10 = 7 · 9 ÷ 1 = 9 · 36 ÷ 6 = 6 · 48 ÷ 12 = 4 · 5 ÷ 1 = 5 · 144 ÷ 12 = 12 · 77 ÷ 7 = 11 · 24 ÷ 3 = 8 · 18 ÷ 9 = 2

About this mystery

Grade level: Grade 3 math
Math topics: Rounding, Addition, Subtraction, Multiplication, Division
Reading level: grades 3-4
Theme: The Lost Idol of Isla Oro — set in the ancient Jungle of Ruins on Isla Oro
Format: Interactive online & printable worksheet with answer key
Solution: One unique, verified culprit among 21 suspects

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