Grade 3Reading: grades 3-4MultiplicationSubtractionAdditionPlace valueMissing addends

The Secret of Spy Island

The Golden Compass has been stolen from the Spy Island Camp vault! The camp director needs your help. Solve the puzzles, gather the clues, and help the junior detectives find the rogue agent!

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 gadget	backup tool	writing style	hair evidence	fended off by
Dash	jetpack	laser watch	left-handed writer	spiky blue hair	squeaky shoes
Penny	disguise kit	decoder ring	right-handed writer	bright orange hair	tickle feathers
Luna	night vision	spy camera	right-handed writer	spiky blue hair	squeaky shoes
Hugo	grappling hook	laser watch	left-handed writer	neon green hair	water balloons
Eli	smoke bomb	zipline belt	right-handed writer	bright orange hair	tickle feathers
Maya	night vision	spy camera	right-handed writer	bright orange hair	tickle feathers
Piper	disguise kit	zipline belt	right-handed writer	neon green hair	tickle feathers
Nova	disguise kit	laser watch	left-handed writer	neon green hair	tickle feathers
Chase	smoke bomb	zipline belt	right-handed writer	spiky blue hair	tickle feathers
Sadie	disguise kit	zipline belt	right-handed writer	spiky blue hair	tickle feathers
Iris	night vision	zipline belt	left-handed writer	spiky blue hair	tickle feathers
Toby	jetpack	decoder ring	right-handed writer	neon green hair	tickle feathers
Ruby	disguise kit	mini drone	right-handed writer	spiky blue hair	squeaky shoes
Max	grappling hook	decoder ring	right-handed writer	spiky blue hair	water balloons
Finn	night vision	decoder ring	left-handed writer	spiky blue hair	squeaky shoes
Zoe	smoke bomb	laser watch	left-handed writer	bright orange hair	tickle feathers
Skye	disguise kit	zipline belt	left-handed writer	spiky blue hair	tickle feathers
Jacks	jetpack	laser watch	right-handed writer	spiky blue hair	tickle feathers
Clara	night vision	zipline belt	right-handed writer	spiky blue hair	tickle feathers
Zane	jetpack	mini drone	right-handed writer	spiky blue hair	tickle feathers
Leo	jetpack	laser watch	right-handed writer	spiky blue hair	squeaky shoes

Clue 1

Multiplication facts (1-12)

We find a stash of gear boxes lined up in neat rows. To count them all quickly, we multiply the rows by the boxes in each row. The total points us to our first 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.

100

121

100

3 × 11 =T

3 × 2 =R

11 × 11 =I

1 × 5 =O

1 × 10 =H

9 × 7 =C

6 × 11 =S

7 × 6 =E

10 × 10 =V

8 × 8 =D

3 × 5 =W

10 × 4 =L

7 × 7 =A

11 × 1 =N

0/14 letters found

Clue 2

Subtraction

The suspect dropped a battery pack. We subtract the leftover power from the starting power to see how long they ran. The difference reveals a secret message.

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

308

514

183

721

521

721

284

183

259

308

159

893

476

308

183

113

758

476

308

183

159

671

308

514

308

514

183

893

671

587

514

308

514

113

758

490

599 - 291 =T

701 - 225 =O

949 - 278 =I

369 - 186 =E

640 - 381 =C

1005 - 284 =S

668 - 154 =H

500 - 387 =A

536 - 252 =P

1171 - 278 =R

864 - 277 =G

744 - 254 =D

984 - 226 =N

409 - 250 =W

776 - 255 =U

0/15 letters found

Clue 3

Addition

Let us total up the footprints found in the mud. We add the prints near the gate to the prints near the wall. The sum unlocks a hidden clue file.

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

927

923

663

311

908

382

923

687

860

587

923

610

370

383

908

370

335

927

370

860

587

860

370

311

784

383

923

967

923

908

860

587

923

382

663

523 + 404 =W

254 + 333 =H

244 + 366 =V

208 + 174 =R

447 + 216 =S

149 + 221 =I

296 + 671 =F

356 + 428 =K

520 + 340 =T

238 + 145 =L

129 + 206 =N

445 + 478 =E

487 + 421 =A

430 + 257 =D

146 + 165 =C

0/15 letters found

Clue 4

Place value

A digital keypad blocks the secret desk. We look at the digits in the hundreds and tens places to crack the login. The open screen shows a suspect trait.

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

5000

300

900

800

6000

200

8000

7000

700

900

600

8000

500

600

1000

900

500

800

What is the value of the 5 in 5,001?W

What is the value of the 3 in 7,534?Y

What is the value of the 6 in 683?H

What is the value of the 2 in 8,254?P

What is the value of the 1 in 3,412?O

What is the value of the 8 in 5,482?E

What is the value of the 5 in 1,518?T

What is the value of the 6 in 168?N

What is the value of the 5 in 7,857?A

What is the value of the 4 in 745?L

What is the value of the 1 in 51,059?V

What is the value of the 6 in 6,939?S

What is the value of the 8 in 2,841?D

What is the value of the 7 in 7,088?K

What is the value of the 3 in 5,389?F

What is the value of the 2 in 729?R

What is the value of the 7 in 790?B

What is the value of the 9 in 1,980?U

What is the value of the 8 in 8,211?I

0/19 letters found

Clue 5

Missing addends — the last clue

We find a weight scale used for packing gear. Some spy tools are missing from the scale. We find the missing number to balance it and get the final clue.

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

1 + ___ = 11

4 + ___ = 8

9 + ___ = 10

5 + ___ = 10

1 + ___ = 13

6 + ___ = 13

6 + ___ = 9

9 + ___ = 11

2 + ___ = 11

8 + ___ = 14

3 + ___ = 11

Step 2 — cross out the sentence with each answer

1.The villain swaps clothes with a mannequin, then zips down the cable.

2.The villain swaps clothes with a mannequin, then snaps a quick photo.

3.The villain vanishes in a puff of smoke, then snaps a quick photo.

4.The villain zooms over the fence, then flies a small camera.

5.The villain vanishes in a puff of smoke, then cuts the vault lock.

6.The villain sneaks through the dark, then cuts the vault lock.

7.The villain swings across the courtyard, then cuts the vault lock.

8.The villain zooms over the fence, then snaps a quick photo.

9.The villain swings across the courtyard, then snaps a quick photo.

10.The villain sneaks through the dark, then zips down the cable.

11.The villain vanishes in a puff of smoke, then zips down the cable.

12.The villain zooms over the fence, then cuts the vault lock.

Solve it

Name the culprit

Choose the one suspect left standing.

Answer Key — The Secret of Spy Island

Culprit: Chase (smoke bomb · zipline belt · right-handed writer · spiky blue hair · tickle feathers)

Clue 1 (Multiplication facts (1-12)): "THE VILLAIN DOES NOT HAVE A LASER WATCH"
3 × 11 = 33 (T) · 3 × 2 = 6 (R) · 11 × 11 = 121 (I) · 1 × 5 = 5 (O) · 1 × 10 = 10 (H) · 9 × 7 = 63 (C) · 6 × 11 = 66 (S) · 7 × 6 = 42 (E) · 10 × 10 = 100 (V) · 8 × 8 = 64 (D) · 3 × 5 = 15 (W) · 10 × 4 = 40 (L) · 7 × 7 = 49 (A) · 11 × 1 = 11 (N)
Clue 2 (Subtraction): "THE SUSPECT WROTE A NOTE WITH THE RIGHT HAND"
599 - 291 = 308 (T) · 701 - 225 = 476 (O) · 949 - 278 = 671 (I) · 369 - 186 = 183 (E) · 640 - 381 = 259 (C) · 1005 - 284 = 721 (S) · 668 - 154 = 514 (H) · 500 - 387 = 113 (A) · 536 - 252 = 284 (P) · 1171 - 278 = 893 (R) · 864 - 277 = 587 (G) · 744 - 254 = 490 (D) · 984 - 226 = 758 (N) · 409 - 250 = 159 (W) · 776 - 255 = 521 (U)
Clue 3 (Addition): "WE SCARED THE VILLAIN WITH TICKLE FEATHERS"
523 + 404 = 927 (W) · 254 + 333 = 587 (H) · 244 + 366 = 610 (V) · 208 + 174 = 382 (R) · 447 + 216 = 663 (S) · 149 + 221 = 370 (I) · 296 + 671 = 967 (F) · 356 + 428 = 784 (K) · 520 + 340 = 860 (T) · 238 + 145 = 383 (L) · 129 + 206 = 335 (N) · 445 + 478 = 923 (E) · 487 + 421 = 908 (A) · 430 + 257 = 687 (D) · 146 + 165 = 311 (C)
Clue 4 (Place value): "WE FOUND SPIKY BLUE HAIR AT THE VAULT DOOR"
What is the value of the 5 in 5,001? = 5000 (W) · What is the value of the 3 in 7,534? = 30 (Y) · What is the value of the 6 in 683? = 600 (H) · What is the value of the 2 in 8,254? = 200 (P) · What is the value of the 1 in 3,412? = 10 (O) · What is the value of the 8 in 5,482? = 80 (E) · What is the value of the 5 in 1,518? = 500 (T) · What is the value of the 6 in 168? = 60 (N) · What is the value of the 5 in 7,857? = 50 (A) · What is the value of the 4 in 745? = 40 (L) · What is the value of the 1 in 51,059? = 1000 (V) · What is the value of the 6 in 6,939? = 6000 (S) · What is the value of the 8 in 2,841? = 800 (D) · What is the value of the 7 in 7,088? = 7000 (K) · What is the value of the 3 in 5,389? = 300 (F) · What is the value of the 2 in 729? = 20 (R) · What is the value of the 7 in 790? = 700 (B) · What is the value of the 9 in 1,980? = 900 (U) · What is the value of the 8 in 8,211? = 8000 (I)
Clue 5 (Missing addends): surviving statement (box 11) → Chase
1 + ___ = 11 = 10 · 4 + ___ = 8 = 4 · 9 + ___ = 10 = 1 · 5 + ___ = 10 = 5 · 1 + ___ = 13 = 12 · 6 + ___ = 13 = 7 · 6 + ___ = 9 = 3 · 9 + ___ = 11 = 2 · 2 + ___ = 11 = 9 · 8 + ___ = 14 = 6 · 3 + ___ = 11 = 8

About this mystery

Grade level: Grade 3 math
Math topics: Multiplication, Subtraction, Addition, Place value, Missing addends
Reading level: grades 3-4
Theme: The Secret of Spy Island — set in Spy Island Camp
Format: Interactive online & printable worksheet with answer key
Solution: One unique, verified culprit among 21 suspects

More free printable math mysteries

3rd grade worksheets Addition worksheets Subtraction worksheets Multiplication worksheets Place value worksheets Missing addends worksheets All worksheets →

The Great Anchovy Heist

Grade 3

The Great Balloon Mystery

Grade 3

The Balloon Fiesta Mystery

Grade 3

The Sandy Flats Sandbox Mystery

Grade 3