Math Crackers
Grade 8Reading: grades 7-9Fractions of a numberRoundingBar modelsExponents

The Sunken Citadel Sabotage

During a midnight expedition inside the Sunken Citadel, a rogue saboteur disabled the vault defense system and stole the priceless Sun Orb. The Lead Expedition Director has secured the perimeter, but the thief is still hidden among the crew. Solve the math challenges to decipher the field notes and unmask the saboteur before they vanish into 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
NamePrimary ToolGadgetGrip StyleExpedition CapCountermeasure
Sergeant KowalskiLaser CutterGlider WingsLeft HandedSilver HelmetEMP Blast
Technician CruzLaser CutterHologram EmitterRight HandedGolden BandanaEMP Blast
Pilot ConnorPlasma TorchSmoke PelletsLeft HandedCrimson CapEMP Blast
Ranger BlakeLaser CutterSignal JammerLeft HandedGolden BandanaAcoustic Shield
Agent FosterLaser CutterHologram EmitterRight HandedCrimson CapEMP Blast
Agent RamirezPlasma TorchSonic DecoyLeft HandedSilver HelmetAcoustic Shield
Professor SterlingLaser CutterGlider WingsLeft HandedCrimson CapEMP Blast
Dr Aris ThorneLaser CutterHologram EmitterLeft HandedSilver HelmetFlashburst Flare
Navigator RossThermal TorchHologram EmitterRight HandedCrimson CapEMP Blast
Operative DiazPlasma TorchSmoke PelletsLeft HandedCrimson CapFlashburst Flare
Analyst KimPlasma TorchSignal JammerLeft HandedGolden BandanaAcoustic Shield
Dr Maya LinSonic DrillHologram EmitterRight HandedSilver HelmetEMP Blast
Specialist MercerLaser CutterSmoke PelletsRight HandedGolden BandanaAcoustic Shield
Scout ChenPlasma TorchSignal JammerLeft HandedSilver HelmetAcoustic Shield
Scholar BennettSonic DrillSmoke PelletsLeft HandedSilver HelmetAcoustic Shield
Chief RiveraSonic DrillHologram EmitterLeft HandedSilver HelmetAcoustic Shield
Captain MarcusPlasma TorchHologram EmitterRight HandedGolden BandanaEMP Blast
Surveyor YoungLaser CutterGlider WingsLeft HandedSilver HelmetAcoustic Shield
Tracker HayesSonic DrillSmoke PelletsRight HandedSilver HelmetAcoustic Shield
Archivist PatelThermal TorchSmoke PelletsLeft HandedGolden BandanaEMP Blast
Officer VanceSonic DrillGlider WingsRight HandedCrimson CapFlashburst Flare
Clue 1

Fractions of a number

We analyzed the energy residue left on the ruined gate to determine how much fuel the intruder used during the breach.

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
45
49
53
3
35
2
2
12
35
19
42
15
53
23
19
15
T
45
55
23
53
12
23
15
19
35
51
42
53
51
15
25
3/8 of 120 =T
2/10 of 95 =N
2/4 of 30 =O
1/3 of 126 =D
4/8 of 24 =A
5/8 of 88 =U
4/8 of 4 =L
1/4 of 100 =Y
5/10 of 46 =S
1/5 of 15 =V
4/8 of 106 =E
2/8 of 196 =H
1/2 of 70 =I
2/6 of 153 =C
0/14 letters found
Clue 2

Rounding

The vault sensors recorded a rough estimate of the intruder weight but the display only rounds to the nearest ten kilograms.

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
5000
500
3000
90
1300
130
130
1300
130
130
70
W
5000
70
2900
1300
1700
3000
300
70
90
30
1300
30
430
20
1300
50
70
3000
500
200
1300
Round 4,509 to the nearest thousandW
Round 20 to the nearest tenP
Round 241 to the nearest hundredV
Round 1,289 to the nearest hundredE
Round 471 to the nearest hundredI
Round 29 to the nearest tenD
Round 3,436 to the nearest thousandT
Round 93 to the nearest tenN
Round 130 to the nearest tenS
Round 2,916 to the nearest hundredL
Round 434 to the nearest tenO
Round 1,684 to the nearest hundredF
Round 66 to the nearest tenA
Round 49 to the nearest tenR
Round 336 to the nearest hundredH
0/15 letters found
Clue 3

Bar model word problems

To compare the power output logs across the different security sectors our team sketched out comparative bar diagrams.

Draw a bar model to solve each word problem. Its answer reveals a letter — write the letters in the boxes to fill in the missing word.

Someonescaredthevillainoffwith
A
20
112
21
62
83
11
72
112
83
H
 
72
E
 
L
 
D
 
.
One group collected 13 relic and another group collected 7 relic. How many relic in all?
draw a bar model
Answer:→A
Expedition Quartermaster has 9 times as many relic as a teammate. The teammate has 8 relic. How many relic does Expedition Quartermaster have?
draw a bar model
Answer:→I
One group collected 6 solar battery and another group collected 5 solar battery. How many solar battery in all?
draw a bar model
Answer:→T
Expedition Quartermaster has 84 map cylinder, packed 4 to a bag. How many bags can be filled?
draw a bar model
Answer:→O
One group collected 40 scanner and another group collected 72 scanner. How many scanner in all?
draw a bar model
Answer:→C
The red team has 101 scanner and the blue team has 39 scanner. How many more scanner does the red team have?
draw a bar model
Answer:→U
There were 120 map cylinder in all. 37 map cylinder were used. How many map cylinder are left?
draw a bar model
Answer:→S
0/7 letters found
Clue 4

Exponents

The security mainframe logged the exponential growth rate of the corrupted code injected into the defense grid.

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

A
729
625
243
225
256
125
400
64
125
225
289
125
144
361
A
729
625
196
400
216
81
81
125
196
A
729
144
144
64
125
625
32
125
8
125
3^6 =A
9^2 =P
19^2 =W
14^2 =D
2^5 =C
5^4 =S
4^4 =V
4^3 =H
2^3 =N
20^2 =R
3^5 =I
17^2 =M
6^3 =O
12^2 =T
5^3 =E
15^2 =L
0/16 letters found
Clue 5

Fractions of a number — the last clue

By calculating the exact fraction of encrypted data packets recovered from the comm tower we unlocked another 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
1/8 of 40 = ?
1/2 of 22 = ?
2/10 of 35 = ?
4/8 of 12 = ?
6/10 of 15 = ?
3/6 of 4 = ?
2/10 of 5 = ?
6/8 of 4 = ?
2/8 of 32 = ?
1/8 of 80 = ?
8/10 of 5 = ?
Step 2 — cross out the sentence with each answer
1.The villain breached the outer wall using a grapple launcher, then soared over the canopy with glider wings.
2.The villain shattered the stone seal using a sonic drill, then soared over the canopy with glider wings.
3.The villain melted the security door using a thermal torch, then disrupted the guard comms with a signal jammer.
4.The villain disintegrated the locks using a plasma torch, then escaped under cover of smoke pellets.
5.The villain shattered the stone seal using a sonic drill, then escaped under cover of smoke pellets.
6.The villain breached the outer wall using a grapple launcher, then distracted the patrol with a sonic decoy.
7.The villain shattered the stone seal using a sonic drill, then confused the pursuers using a hologram emitter.
8.The villain breached the outer wall using a grapple launcher, then disrupted the guard comms with a signal jammer.
9.The villain melted the security door using a thermal torch, then escaped under cover of smoke pellets.
10.The villain breached the outer wall using a grapple launcher, then confused the pursuers using a hologram emitter.
11.The villain sliced through the reinforced vault using a laser cutter, then soared over the canopy with glider wings.
12.The villain disintegrated the locks using a plasma torch, then disrupted the guard comms with a signal jammer.
Solve it

Name the culprit

Choose the one suspect left standing.

About this mystery

Grade level
Grade 8 math
Math topics
Fractions of a number, Rounding, Bar models, Exponents
Reading level
grades 7-9
Theme
The Sunken Citadel Sabotage — set in Sunken Citadel in the Amazon basin
Format
Interactive online & printable worksheet with answer key
Solution
One unique, verified culprit among 21 suspects

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