Grade 9Reading: grades 7-9Two-step equationsExponentsSquare rootsIntegers
The Echo Caverns Robbery
Someone has raided the central vault of the Echo Caverns and swiped the legendary Crystal Compass! The Head Archeologist needs your help. You must analyze the evidence left behind, solve the math puzzles to unlock the secure databases, and identify the rogue explorer before they escape the caverns forever!
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 Tool | Special Gear | Observed Grip | Leftover Hair Evidence | Effective Defense |
|---|---|---|---|---|---|
| Jack Hunter | decoding tablet | climbing spikes | left-handed grip | bright orange hair | bright flashlights |
| Alan Grant | decoding tablet | jet boots | right-handed grip | bright orange hair | bright flashlights |
| Carmen Sandiego | laser cutter | climbing spikes | left-handed grip | bright orange hair | sticky mud traps |
| Charles Lindbergh | sonic blaster | portable zipline | right-handed grip | dusty brown hair | bright flashlights |
| Ellie Sattler | decoding tablet | climbing spikes | right-handed grip | bright orange hair | sticky mud traps |
| Robert Peary | grappling hook | jet boots | right-handed grip | bright orange hair | sticky mud traps |
| Mary Kingsley | drone controller | night vision visor | left-handed grip | bright orange hair | loud whistles |
| Dirk Pitt | decoding tablet | jet boots | left-handed grip | dusty brown hair | bright flashlights |
| Jacques Cousteau | drone controller | night vision visor | right-handed grip | bright orange hair | bright flashlights |
| Benjamin Gates | decoding tablet | night vision visor | right-handed grip | bright orange hair | sticky mud traps |
| Roy Chapman | grappling hook | jet boots | right-handed grip | bright orange hair | loud whistles |
| Nellie Bly | drone controller | stealth cloak | right-handed grip | dusty brown hair | loud whistles |
| Rick OConnell | grappling hook | stealth cloak | right-handed grip | neon blue hair | loud whistles |
| Nathan Drake | decoding tablet | stealth cloak | left-handed grip | neon blue hair | loud whistles |
| Hiram Bingham | drone controller | stealth cloak | right-handed grip | bright orange hair | sticky mud traps |
| Lara Croft | grappling hook | night vision visor | right-handed grip | neon blue hair | sticky mud traps |
| Sacagawea | drone controller | climbing spikes | right-handed grip | neon blue hair | sticky mud traps |
| Sly Cooper | sonic blaster | jet boots | right-handed grip | dusty brown hair | bright flashlights |
| Steve Irwin | decoding tablet | jet boots | right-handed grip | dusty brown hair | bright flashlights |
| Amelia Earhart | drone controller | night vision visor | right-handed grip | neon blue hair | loud whistles |
| Percy Fawcett | decoding tablet | jet boots | right-handed grip | bright orange hair | sticky mud traps |
Clue 1
Two-step equations
To crack the ancient pressure-pad door, we must balance the weight equation of the stone blocks.
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
11
9
15
16
18
4
4
8
18
2
17
10
15
12
2
10
T
11
5
12
15
8
12
T
11
15
8
4
T
11
9
7
4
10
8
22
3x + 6 = 39, x =T
7x + 10 = 122, x =V
8x + 5 = 61, x =C
2x + 6 = 30, x =S
8x + 3 = 83, x =O
2x + 11 = 41, x =E
3x + 2 = 29, x =H
6x + 6 = 138, x =K
9x + 8 = 26, x =N
3x + 5 = 56, x =D
5x + 11 = 36, x =U
5x + 11 = 31, x =L
6x + 10 = 118, x =I
7x + 2 = 58, x =A
0/14 letters found
Clue 2
Exponents
A colony of cave scarabs is multiplying fast, and we need to calculate their exponential growth to clear the path.
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
484
49
729
144
8
144
361
729
25
T
484
27
729
441
T
484
125
36
100
243
49
T
484
49
125
64
256
729
256
243
36
100
361
22^2 =T
2^6 =N
5^2 =C
9^3 =E
7^2 =H
12^2 =S
10^2 =I
3^3 =L
2^3 =U
19^2 =P
21^2 =F
5^3 =A
6^2 =R
4^4 =D
3^5 =G
0/15 letters found
Clue 3
Square roots
The security laser grid is shaped like a perfect square, so finding its side length will let us slip through safely.
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
10
3
18
13
17
6
T
10
11
T
10
5
4
23
15
20
11
T
10
15
4
23
13
25
5
9
T
10
19
14
16
11
sqrt(100) =T
sqrt(225) =I
sqrt(9) =H
sqrt(16) =C
sqrt(529) =K
sqrt(289) =G
sqrt(169) =Y
sqrt(400) =N
sqrt(25) =U
sqrt(36) =O
sqrt(121) =S
sqrt(196) =A
sqrt(625) =M
sqrt(256) =P
sqrt(361) =R
sqrt(324) =E
sqrt(81) =D
0/17 letters found
Clue 4
Integers
We are descending deep into the freezing sub-zero caverns, where we must track our changing elevation in negative integers.
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
21
20
1
39
32
1
7
1
32
35
7
T
21
34
10
7
1
30
2
28
10
4
20
T
21
35
28
34
7
4
1
20
34
10
28
15 - (-6) =T
(-14) + 21 =N
2 - (-8) =I
13 - (-15) =R
15 - (-5) =H
15 - (-15) =D
(-9) + 11 =B
(-10) + 11 =E
(-11) + 15 =G
(-10) + 49 =S
(-9) + 41 =C
(-9) + 44 =O
(-8) + 42 =A
0/13 letters found
Clue 5
Two-step equations — the last clue
To power up the escape minecart, we need to solve the dual-stage fuel mixture equation before the countdown ends.
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
6x + 9 = 45, x = ?
6x + 11 = 41, x = ?
3x + 12 = 39, x = ?
3x + 2 = 35, x = ?
6x + 6 = 78, x = ?
7x + 10 = 24, x = ?
4x + 5 = 9, x = ?
4x + 12 = 24, x = ?
8x + 3 = 59, x = ?
2x + 3 = 19, x = ?
2x + 8 = 16, x = ?
Step 2 — cross out the sentence with each answer
1.The villain shatters the crystalline barrier with a sonic blaster, then fades into the shadows with a stealth cloak.
2.The villain bypasses the digital security lock with a decoding tablet, then slides down to the lower basin on a portable zipline.
3.The villain swings across the cavern chasm with a grappling hook, then navigates the pitch-black tunnels with a night vision visor.
4.The villain slices through the heavy steel vault doors with a laser cutter, then fades into the shadows with a stealth cloak.
5.The villain bypasses the digital security lock with a decoding tablet, then navigates the pitch-black tunnels with a night vision visor.
6.The villain bypasses the digital security lock with a decoding tablet, then rockets over the lava pool with jet boots.
7.The villain scouts the escape route using a drone controller, then scales the sheer rock wall using climbing spikes.
8.The villain shatters the crystalline barrier with a sonic blaster, then rockets over the lava pool with jet boots.
9.The villain bypasses the digital security lock with a decoding tablet, then scales the sheer rock wall using climbing spikes.
10.The villain swings across the cavern chasm with a grappling hook, then rockets over the lava pool with jet boots.
11.The villain shatters the crystalline barrier with a sonic blaster, then slides down to the lower basin on a portable zipline.
12.The villain swings across the cavern chasm with a grappling hook, then slides down to the lower basin on a portable zipline.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Echo Caverns Robbery
Culprit: Robert Peary (grappling hook · jet boots · right-handed grip · bright orange hair · sticky mud traps)
- Clue 1 (Two-step equations): "THE VILLAIN DOES NOT USE A STEALTH CLOAK"3x + 6 = 39, x = 11 (T) · 7x + 10 = 122, x = 16 (V) · 8x + 5 = 61, x = 7 (C) · 2x + 6 = 30, x = 12 (S) · 8x + 3 = 83, x = 10 (O) · 2x + 11 = 41, x = 15 (E) · 3x + 2 = 29, x = 9 (H) · 6x + 6 = 138, x = 22 (K) · 9x + 8 = 26, x = 2 (N) · 3x + 5 = 56, x = 17 (D) · 5x + 11 = 36, x = 5 (U) · 5x + 11 = 31, x = 4 (L) · 6x + 10 = 118, x = 18 (I) · 7x + 2 = 58, x = 8 (A)
- Clue 2 (Exponents): "THE SUSPECT LEFT A RIGHTHANDED GRIP"22^2 = 484 (T) · 2^6 = 64 (N) · 5^2 = 25 (C) · 9^3 = 729 (E) · 7^2 = 49 (H) · 12^2 = 144 (S) · 10^2 = 100 (I) · 3^3 = 27 (L) · 2^3 = 8 (U) · 19^2 = 361 (P) · 21^2 = 441 (F) · 5^3 = 125 (A) · 6^2 = 36 (R) · 4^4 = 256 (D) · 3^5 = 243 (G)
- Clue 3 (Square roots): "THEY GOT STUCK IN STICKY MUD TRAPS"sqrt(100) = 10 (T) · sqrt(225) = 15 (I) · sqrt(9) = 3 (H) · sqrt(16) = 4 (C) · sqrt(529) = 23 (K) · sqrt(289) = 17 (G) · sqrt(169) = 13 (Y) · sqrt(400) = 20 (N) · sqrt(25) = 5 (U) · sqrt(36) = 6 (O) · sqrt(121) = 11 (S) · sqrt(196) = 14 (A) · sqrt(625) = 25 (M) · sqrt(256) = 16 (P) · sqrt(361) = 19 (R) · sqrt(324) = 18 (E) · sqrt(81) = 9 (D)
- Clue 4 (Integers): "THE SCENE CONTAINED BRIGHT ORANGE HAIR"15 - (-6) = 21 (T) · (-14) + 21 = 7 (N) · 2 - (-8) = 10 (I) · 13 - (-15) = 28 (R) · 15 - (-5) = 20 (H) · 15 - (-15) = 30 (D) · (-9) + 11 = 2 (B) · (-10) + 11 = 1 (E) · (-11) + 15 = 4 (G) · (-10) + 49 = 39 (S) · (-9) + 41 = 32 (C) · (-9) + 44 = 35 (O) · (-8) + 42 = 34 (A)
- Clue 5 (Two-step equations): surviving statement (box 10) → Robert Peary6x + 9 = 45, x = 6 · 6x + 11 = 41, x = 5 · 3x + 12 = 39, x = 9 · 3x + 2 = 35, x = 11 · 6x + 6 = 78, x = 12 · 7x + 10 = 24, x = 2 · 4x + 5 = 9, x = 1 · 4x + 12 = 24, x = 3 · 8x + 3 = 59, x = 7 · 2x + 3 = 19, x = 8 · 2x + 8 = 16, x = 4
About this mystery
- Grade level
- Grade 9 math
- Math topics
- Two-step equations, Exponents, Square roots, Integers
- Reading level
- grades 7-9
- Theme
- The Echo Caverns Robbery — set in The Echo Caverns
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects