Grade 4Reading: grades 3-4RoundingMulti-step word problemsWord problemsAdditionMissing addends
The Case of the Missing Star Crystal
Someone sneaked into the Starlight Observatory and snatched the glowing Cosmic Crystal right off the telescope mount! Use your detective skills to decode clues and stop 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 | Gadget | Booster | Glove Type | Helmet Stripe | Distraction |
|---|---|---|---|---|---|
| Ava Galaxy | Laser Torch | Turbo Dash | Right Glove | Electric Blue | Shiny Coins |
| Leo Orion | Laser Torch | Rocket Skates | Right Glove | Electric Blue | Shiny Coins |
| Cosmo Jack | Freeze Ray | Turbo Dash | Right Glove | Neon Silver | Bubble Gum |
| Ruby Orbit | Freeze Ray | Solar Wings | Right Glove | Copper Gold | Squeaky Toys |
| Toby Quasar | Hover Board | Turbo Dash | Left Glove | Copper Gold | Squeaky Toys |
| Penny Starlight | Freeze Ray | Jet Pack | Left Glove | Electric Blue | Shiny Coins |
| Maya Nova | Freeze Ray | Rocket Skates | Left Glove | Neon Silver | Squeaky Toys |
| Kai Eclipse | Freeze Ray | Rocket Skates | Left Glove | Electric Blue | Squeaky Toys |
| Zoe Comet | Grapple Hook | Turbo Dash | Left Glove | Electric Blue | Bubble Gum |
| Nora Aurora | Laser Torch | Gravity Boots | Right Glove | Electric Blue | Shiny Coins |
| Wren Sol | Grapple Hook | Rocket Skates | Right Glove | Electric Blue | Squeaky Toys |
| Jax Nebula | Grapple Hook | Solar Wings | Right Glove | Electric Blue | Shiny Coins |
| Luna Star | Hover Board | Jet Pack | Left Glove | Copper Gold | Shiny Coins |
| Hugo Gravity | Hover Board | Solar Wings | Right Glove | Copper Gold | Bubble Gum |
| Max Pulsar | Hover Board | Jet Pack | Right Glove | Electric Blue | Shiny Coins |
| Cleo Photon | Sonic Whistle | Solar Wings | Right Glove | Neon Silver | Bubble Gum |
| Sam Rocket | Sonic Whistle | Gravity Boots | Right Glove | Copper Gold | Bubble Gum |
| Astro Ben | Hover Board | Jet Pack | Left Glove | Neon Silver | Squeaky Toys |
| Finn Zenith | Freeze Ray | Rocket Skates | Right Glove | Copper Gold | Shiny Coins |
| Ivy Meteor | Laser Torch | Jet Pack | Right Glove | Neon Silver | Bubble Gum |
| Tess Horizon | Laser Torch | Rocket Skates | Right Glove | Electric Blue | Squeaky Toys |
Clue 1
Rounding
The station computer logs show energy usage from the observatory room. Solve this problem to unlock the 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.
T
290
2300
430
9000
1700
500
900
2000
200
T
290
3700
2900
430
1100
700
2900
T
290
70
430
50
2000
370
2000
50
170
200
T
290
4300
30
2900
2900
T
290
1100
Round 286 to the nearest tenT
Round 8,551 to the nearest thousandC
Round 1,685 to the nearest hundredU
Round 54 to the nearest tenA
Round 4,323 to the nearest hundredY
Round 72 to the nearest tenW
Round 32 to the nearest tenB
Round 370 to the nearest tenG
Round 2,348 to the nearest hundredH
Round 167 to the nearest hundredI
Round 488 to the nearest hundredL
Round 1,138 to the nearest hundredS
Round 2,388 to the nearest thousandR
Round 433 to the nearest tenE
Round 863 to the nearest hundredP
Round 168 to the nearest tenV
Round 713 to the nearest hundredN
Round 3,680 to the nearest hundredD
Round 2,875 to the nearest hundredO
0/19 letters found
Clue 2
Multi-step word problems
To track down the culprit, Cadets must calculate the total fuel used across multiple supply stops.
Solve each problem to learn its letter, then write the letters in the boxes to fill in the missing word.
Awitnesssawthevillainwas .
R
56
39
87
90
77
87
68
64
V
E
There were 465 star crystals in all. 17 star crystals were set aside. The rest were shared equally among 8 Starlight Rangers. How many star crystals did each get?R
There were 252 moon rocks in all. 21 moon rocks were set aside. The rest were shared equally among 3 Starlight Rangers. How many moon rocks did each get?T
Cadet Captain filled 6 boxes with 4 cosmic maps each, then found 15 more cosmic maps. How many cosmic maps are there in all?I
Cadet Captain earned 7 moon rocks in each of 4 rounds, plus 60 bonus moon rocks. Then 1 moon rocks were lost. How many moon rocks are left?G
Cadet Captain earned 8 moon rocks in each of 3 rounds, plus 51 bonus moon rocks. Then 11 moon rocks were lost. How many moon rocks are left?O
Cadet Captain filled 6 boxes with 6 moon rocks each, then found 32 more moon rocks. How many moon rocks are there in all?L
There were 522 star crystals in all. 2 Starlight Rangers used 36 star crystals each. The other 5 Starlight Rangers shared the rest equally. How many star crystals did each of the other Starlight Rangers get?H
0/7 letters found
Clue 3
Word problems
The station radar scanner only shows rough rounded distance numbers for safety reasons.
Solve each problem to learn its letter, then write the letters in the boxes to fill in the missing word.
Someonescaredthevillainoffwith.
S
36
37
66
32
25
60
64
66
32
S
36
Cadet Captain lined up 12 rows of 3 space badges. How many space badges in all?S
Cadet Captain found 11 cosmic maps yesterday and 14 more today. How many cosmic maps in all?Y
Cadet Captain found 2 moon rocks yesterday and 30 more today. How many moon rocks in all?N
Cadet Captain lined up 8 rows of 8 cosmic maps. How many cosmic maps in all?O
Cadet Captain found 25 moon rocks yesterday and 12 more today. How many moon rocks in all?H
Cadet Captain lined up 11 rows of 6 star crystals. How many star crystals in all?I
Cadet Captain lined up 5 rows of 12 star crystals. How many star crystals in all?C
0/7 letters found
Clue 4
Addition
The cadet officer tallied up the extra footprints left near the observation deck.
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
3938
4791
9719
5328
9719
6568
9706
5046
4104
6568
9642
5328
2119
9719
3638
9706
5046
4104
4997
9719
8225
5328
A
3938
5079
9719
5432
A
3938
3638
5328
9719
8225
9706
9642
9719
7663
4104
4791
6827
2055 + 1883 =A
2401 + 2927 =L
3931 + 5775 =T
3212 + 2220 =W
4299 + 2528 =D
1858 + 3221 =K
2259 + 1379 =S
4922 + 4797 =E
5065 + 4577 =B
811 + 1308 =U
2326 + 4242 =C
2786 + 5439 =F
4187 + 3476 =H
2451 + 1653 =I
2861 + 1930 =N
1713 + 3284 =P
3238 + 1808 =R
0/17 letters found
Clue 5
Missing addends — the last clue
The security locker has a missing code digit needed to match the evidence vault.
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
36 + ___ = 44
40 + ___ = 43
4 + ___ = 8
38 + ___ = 50
10 + ___ = 21
32 + ___ = 41
30 + ___ = 40
12 + ___ = 18
27 + ___ = 29
28 + ___ = 35
37 + ___ = 42
Step 2 — cross out the sentence with each answer
1.The villain melted the vault hinge with a laser torch, then dashed out the airlock with turbo dash.
2.The villain blasted open the panel with a sonic whistle, then fled high into the rafters using a jet pack.
3.The villain zapped the vault lock with a grapple hook, then glided over the fence with solar wings.
4.The villain melted the vault hinge with a laser torch, then skated past guards using rocket skates.
5.The villain zoomed through security on a hover board, then skated past guards using rocket skates.
6.The villain froze the alarm sensors with a freeze ray, then skated past guards using rocket skates.
7.The villain blasted open the panel with a sonic whistle, then strode across the ceiling wearing gravity boots.
8.The villain zoomed through security on a hover board, then fled high into the rafters using a jet pack.
9.The villain zoomed through security on a hover board, then dashed out the airlock with turbo dash.
10.The villain froze the alarm sensors with a freeze ray, then glided over the fence with solar wings.
11.The villain blasted open the panel with a sonic whistle, then skated past guards using rocket skates.
12.The villain melted the vault hinge with a laser torch, then strode across the ceiling wearing gravity boots.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Case of the Missing Star Crystal
Culprit: Ava Galaxy (Laser Torch · Turbo Dash · Right Glove · Electric Blue · Shiny Coins)
- Clue 1 (Rounding): "THE CULPRIT DOES NOT WEAR GRAVITY BOOTS"Round 286 to the nearest ten = 290 (T) · Round 8,551 to the nearest thousand = 9000 (C) · Round 1,685 to the nearest hundred = 1700 (U) · Round 54 to the nearest ten = 50 (A) · Round 4,323 to the nearest hundred = 4300 (Y) · Round 72 to the nearest ten = 70 (W) · Round 32 to the nearest ten = 30 (B) · Round 370 to the nearest ten = 370 (G) · Round 2,348 to the nearest hundred = 2300 (H) · Round 167 to the nearest hundred = 200 (I) · Round 488 to the nearest hundred = 500 (L) · Round 1,138 to the nearest hundred = 1100 (S) · Round 2,388 to the nearest thousand = 2000 (R) · Round 433 to the nearest ten = 430 (E) · Round 863 to the nearest hundred = 900 (P) · Round 168 to the nearest ten = 170 (V) · Round 713 to the nearest hundred = 700 (N) · Round 3,680 to the nearest hundred = 3700 (D) · Round 2,875 to the nearest hundred = 2900 (O)
- Clue 2 (Multi-step word problems): "RIGHT GLOVE"There were 465 star crystals in all. 17 star crystals were set aside. The rest were shared equally among 8 Starlight Rangers. How many star crystals did each get? = 56 (R) · There were 252 moon rocks in all. 21 moon rocks were set aside. The rest were shared equally among 3 Starlight Rangers. How many moon rocks did each get? = 77 (T) · Cadet Captain filled 6 boxes with 4 cosmic maps each, then found 15 more cosmic maps. How many cosmic maps are there in all? = 39 (I) · Cadet Captain earned 7 moon rocks in each of 4 rounds, plus 60 bonus moon rocks. Then 1 moon rocks were lost. How many moon rocks are left? = 87 (G) · Cadet Captain earned 8 moon rocks in each of 3 rounds, plus 51 bonus moon rocks. Then 11 moon rocks were lost. How many moon rocks are left? = 64 (O) · Cadet Captain filled 6 boxes with 6 moon rocks each, then found 32 more moon rocks. How many moon rocks are there in all? = 68 (L) · There were 522 star crystals in all. 2 Starlight Rangers used 36 star crystals each. The other 5 Starlight Rangers shared the rest equally. How many star crystals did each of the other Starlight Rangers get? = 90 (H)
- Clue 3 (Word problems): "SHINY COINS"Cadet Captain lined up 12 rows of 3 space badges. How many space badges in all? = 36 (S) · Cadet Captain found 11 cosmic maps yesterday and 14 more today. How many cosmic maps in all? = 25 (Y) · Cadet Captain found 2 moon rocks yesterday and 30 more today. How many moon rocks in all? = 32 (N) · Cadet Captain lined up 8 rows of 8 cosmic maps. How many cosmic maps in all? = 64 (O) · Cadet Captain found 25 moon rocks yesterday and 12 more today. How many moon rocks in all? = 37 (H) · Cadet Captain lined up 11 rows of 6 star crystals. How many star crystals in all? = 66 (I) · Cadet Captain lined up 5 rows of 12 star crystals. How many star crystals in all? = 60 (C)
- Clue 4 (Addition): "AN ELECTRIC BLUE STRIPE FLAKE WAS LEFT BEHIND"2055 + 1883 = 3938 (A) · 2401 + 2927 = 5328 (L) · 3931 + 5775 = 9706 (T) · 3212 + 2220 = 5432 (W) · 4299 + 2528 = 6827 (D) · 1858 + 3221 = 5079 (K) · 2259 + 1379 = 3638 (S) · 4922 + 4797 = 9719 (E) · 5065 + 4577 = 9642 (B) · 811 + 1308 = 2119 (U) · 2326 + 4242 = 6568 (C) · 2786 + 5439 = 8225 (F) · 4187 + 3476 = 7663 (H) · 2451 + 1653 = 4104 (I) · 2861 + 1930 = 4791 (N) · 1713 + 3284 = 4997 (P) · 3238 + 1808 = 5046 (R)
- Clue 5 (Missing addends): surviving statement (box 1) → Ava Galaxy36 + ___ = 44 = 8 · 40 + ___ = 43 = 3 · 4 + ___ = 8 = 4 · 38 + ___ = 50 = 12 · 10 + ___ = 21 = 11 · 32 + ___ = 41 = 9 · 30 + ___ = 40 = 10 · 12 + ___ = 18 = 6 · 27 + ___ = 29 = 2 · 28 + ___ = 35 = 7 · 37 + ___ = 42 = 5
About this mystery
- Grade level
- Grade 4 math
- Math topics
- Rounding, Multi-step word problems, Word problems, Addition, Missing addends
- Reading level
- grades 3-4
- Theme
- The Case of the Missing Star Crystal — set in Starlight Space Station HQ
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects