Grade 4Reading: grades 3-4AdditionSubtractionRoundingWord problemsDivision

Mystery of the Crystal Map

Someone snuck into the camp tent and took the ancient crystal map! Use your math skills to narrow down the suspects and catch the thief.

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	Primary Gear	Badge Emblem	Dominant Hand	Hat Color	Feared Sound
Hunter Hank	Pocket Telescope	Wolf Emblem	Right-handed	Blue Cap	Bright Flash
Trooper Troy	Smoke Pellet	Bear Emblem	Left-handed	Blue Cap	Squeaky Toy
Navigator Ned	Smoke Pellet	Snake Emblem	Right-handed	Green Cap	Bright Flash
Chief Chris	Grappling Hook	Snake Emblem	Left-handed	Red Cap	Squeaky Toy
Rider Rose	Smoke Pellet	Tiger Emblem	Left-handed	Blue Cap	Loud Whistle
Skier Sean	Compass Watch	Bear Emblem	Left-handed	Green Cap	Squeaky Toy
Tracker Tom	Smoke Pellet	Tiger Emblem	Left-handed	Blue Cap	Bright Flash
Pathfinder Pete	Grappling Hook	Bear Emblem	Right-handed	Green Cap	Loud Whistle
Rover Ruby	Smoke Pellet	Wolf Emblem	Left-handed	Blue Cap	Loud Whistle
Sailor Sally	Pocket Telescope	Bear Emblem	Left-handed	Blue Cap	Loud Whistle
Guide Grace	Night Goggles	Falcon Emblem	Left-handed	Blue Cap	Squeaky Toy
Ranger Rick	Pocket Telescope	Tiger Emblem	Right-handed	Blue Cap	Squeaky Toy
Maya Swift	Pocket Telescope	Tiger Emblem	Right-handed	Blue Cap	Loud Whistle
Pilot Penny	Pocket Telescope	Falcon Emblem	Left-handed	Blue Cap	Squeaky Toy
Leo Bold	Grappling Hook	Snake Emblem	Left-handed	Blue Cap	Loud Whistle
Agent Andy	Night Goggles	Falcon Emblem	Left-handed	Red Cap	Loud Whistle
Explorer Elsa	Night Goggles	Snake Emblem	Left-handed	Blue Cap	Bright Flash
Captain Cole	Pocket Telescope	Tiger Emblem	Right-handed	Red Cap	Squeaky Toy
Trapper Tim	Compass Watch	Bear Emblem	Right-handed	Green Cap	Squeaky Toy
Climber Carl	Grappling Hook	Falcon Emblem	Left-handed	Blue Cap	Loud Whistle
Driver Daisy	Grappling Hook	Tiger Emblem	Left-handed	Red Cap	Bright Flash

Clue 1

Addition

We counted up all the tracks found near the supply tent to narrow down the emblem list.

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

7947

2371

3899

7170

4609

7170

6611

3899

2191

7947

6491

4050

3899

7170

7136

4050

7947

3056

3899

7000

4960

7000

3280

3899

7000

4960

3899

3142

3280

3876

3899

3142

2709 + 5238 =T

1439 + 2460 =E

2496 + 4115 =P

3242 + 3894 =N

4076 + 2924 =A

4525 + 1966 =D

680 + 1511 =C

1085 + 1286 =H

1024 + 2118 =M

2054 + 2906 =R

2372 + 1678 =O

2732 + 1877 =U

1227 + 1829 =W

4760 + 2410 =S

1507 + 2369 =L

1434 + 1846 =B

0/16 letters found

Clue 2

Subtraction

Comparing the lost gear to what remains helped us figure out the thief's dominant hand.

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

2603

8470

5210

7484

6010

2603

5583

6366

7123

1774

2603

6346

8470

6010

4905

3969

4957

5210

7484

2603

8470

3969

1774

3333

5210

3333

6346

2603

6366

7123

3333

5210

6672 - 4069 =T

7548 - 3579 =A

8432 - 1309 =I

5433 - 223 =E

10558 - 4975 =P

10979 - 3495 =F

9679 - 4774 =W

10208 - 3842 =R

10863 - 2393 =H

6373 - 27 =S

9470 - 3460 =O

5113 - 3339 =N

6958 - 3625 =D

7042 - 2085 =L

0/14 letters found

Clue 3

Rounding

The motion detector display rounded off the distance, giving us a quick hint about their gear.

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

430

7000

130

1300

7000

700

2000

1300

700

1700

2000

900

300

1300

130

900

3000

110

370

7000

4300

130

430

Round 70 to the nearest tenT

Round 4,287 to the nearest hundredS

Round 2,588 to the nearest thousandU

Round 109 to the nearest tenD

Round 272 to the nearest hundredM

Round 26 to the nearest tenH

Round 372 to the nearest tenW

Round 1,729 to the nearest hundredF

Round 1,999 to the nearest thousandR

Round 18 to the nearest tenV

Round 7,487 to the nearest thousandI

Round 686 to the nearest hundredN

Round 911 to the nearest hundredO

Round 1,345 to the nearest hundredA

Round 429 to the nearest tenE

Round 129 to the nearest tenL

0/16 letters found

Clue 4

Word problems

Working out how many trail snacks were packed per scout revealed another key piece of evidence.

Solve each problem to learn its letter, then write the letters in the boxes to fill in the missing word.

Astrandof

hairturnedupatthescene.

There were 47 rope coil. 38 were used up. How many rope coil are left?B

Trail guide lined up 8 rows of 10 compass. How many compass in all?U

Trail guide lined up 8 rows of 8 flashlight. How many flashlight in all?E

There were 52 rope coil. 13 were used up. How many rope coil are left?L

There were 108 flashlight. 36 were used up. How many flashlight are left?P

Trail guide found 53 canteen yesterday and 21 more today. How many canteen in all?A

Trail guide found 12 rope coil yesterday and 9 more today. How many rope coil in all?C

0/7 letters found

Clue 5

Division facts (1-12) — the last clue

Dividing the clue cards equally among our team led us to the final detail about the hat color.

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

50 ÷ 5 = ?

121 ÷ 11 = ?

21 ÷ 3 = ?

15 ÷ 5 = ?

54 ÷ 9 = ?

54 ÷ 6 = ?

4 ÷ 4 = ?

45 ÷ 9 = ?

20 ÷ 5 = ?

72 ÷ 9 = ?

24 ÷ 12 = ?

Step 2 — cross out the sentence with each answer

1.The villain checked the time with a compass watch, then pinned on a golden tiger emblem.

2.The villain scouted the dark trail with night goggles, then flashed a shiny falcon emblem.

3.The villain scouted the dark trail with night goggles, then polished a carved snake emblem.

4.The villain spotted the path using a pocket telescope, then showed off a silver wolf emblem.

5.The villain checked the time with a compass watch, then flashed a shiny falcon emblem.

6.The villain swung across the river with a grappling hook, then pinned on a golden tiger emblem.

7.The villain vanished into the trees with a smoke pellet, then pinned on a golden tiger emblem.

8.The villain vanished into the trees with a smoke pellet, then polished a carved snake emblem.

9.The villain spotted the path using a pocket telescope, then pinned on a golden tiger emblem.

10.The villain swung across the river with a grappling hook, then polished a carved snake emblem.

11.The villain vanished into the trees with a smoke pellet, then showed off a silver wolf emblem.

12.The villain swung across the river with a grappling hook, then flashed a shiny falcon emblem.

Solve it

Name the culprit

Choose the one suspect left standing.

Answer Key — Mystery of the Crystal Map

Culprit: Climber Carl (Grappling Hook · Falcon Emblem · Left-handed · Blue Cap · Loud Whistle)

Clue 1 (Addition): "THE SUSPECT DOES NOT WEAR A BEAR EMBLEM"
2709 + 5238 = 7947 (T) · 1439 + 2460 = 3899 (E) · 2496 + 4115 = 6611 (P) · 3242 + 3894 = 7136 (N) · 4076 + 2924 = 7000 (A) · 4525 + 1966 = 6491 (D) · 680 + 1511 = 2191 (C) · 1085 + 1286 = 2371 (H) · 1024 + 2118 = 3142 (M) · 2054 + 2906 = 4960 (R) · 2372 + 1678 = 4050 (O) · 2732 + 1877 = 4609 (U) · 1227 + 1829 = 3056 (W) · 4760 + 2410 = 7170 (S) · 1507 + 2369 = 3876 (L) · 1434 + 1846 = 3280 (B)
Clue 2 (Subtraction): "THE FOOTPRINTS SHOW A LEFT HANDED STRIDE"
6672 - 4069 = 2603 (T) · 7548 - 3579 = 3969 (A) · 8432 - 1309 = 7123 (I) · 5433 - 223 = 5210 (E) · 10558 - 4975 = 5583 (P) · 10979 - 3495 = 7484 (F) · 9679 - 4774 = 4905 (W) · 10208 - 3842 = 6366 (R) · 10863 - 2393 = 8470 (H) · 6373 - 27 = 6346 (S) · 9470 - 3460 = 6010 (O) · 5113 - 3339 = 1774 (N) · 6958 - 3625 = 3333 (D) · 7042 - 2085 = 4957 (L)
Clue 3 (Rounding): "THE VILLAIN RAN FROM A LOUD WHISTLE"
Round 70 to the nearest ten = 70 (T) · Round 4,287 to the nearest hundred = 4300 (S) · Round 2,588 to the nearest thousand = 3000 (U) · Round 109 to the nearest ten = 110 (D) · Round 272 to the nearest hundred = 300 (M) · Round 26 to the nearest ten = 30 (H) · Round 372 to the nearest ten = 370 (W) · Round 1,729 to the nearest hundred = 1700 (F) · Round 1,999 to the nearest thousand = 2000 (R) · Round 18 to the nearest ten = 20 (V) · Round 7,487 to the nearest thousand = 7000 (I) · Round 686 to the nearest hundred = 700 (N) · Round 911 to the nearest hundred = 900 (O) · Round 1,345 to the nearest hundred = 1300 (A) · Round 429 to the nearest ten = 430 (E) · Round 129 to the nearest ten = 130 (L)
Clue 4 (Word problems): "BLUE CAP"
There were 47 rope coil. 38 were used up. How many rope coil are left? = 9 (B) · Trail guide lined up 8 rows of 10 compass. How many compass in all? = 80 (U) · Trail guide lined up 8 rows of 8 flashlight. How many flashlight in all? = 64 (E) · There were 52 rope coil. 13 were used up. How many rope coil are left? = 39 (L) · There were 108 flashlight. 36 were used up. How many flashlight are left? = 72 (P) · Trail guide found 53 canteen yesterday and 21 more today. How many canteen in all? = 74 (A) · Trail guide found 12 rope coil yesterday and 9 more today. How many rope coil in all? = 21 (C)
Clue 5 (Division facts (1-12)): surviving statement (box 12) → Climber Carl
50 ÷ 5 = 10 · 121 ÷ 11 = 11 · 21 ÷ 3 = 7 · 15 ÷ 5 = 3 · 54 ÷ 9 = 6 · 54 ÷ 6 = 9 · 4 ÷ 4 = 1 · 45 ÷ 9 = 5 · 20 ÷ 5 = 4 · 72 ÷ 9 = 8 · 24 ÷ 12 = 2

About this mystery

Grade level: Grade 4 math
Math topics: Addition, Subtraction, Rounding, Word problems, Division
Reading level: grades 3-4
Theme: Mystery of the Crystal Map — set in Misty Island Jungle
Format: Interactive online & printable worksheet with answer key
Solution: One unique, verified culprit among 21 suspects

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