Grade 3Reading: grades 3-4RoundingAdditionSubtractionMultiplicationDivision
The Secret Treehouse Caper
Oh no! Someone broke into the Treehouse HQ and took the Golden Juice Box Blueprint! Only a certified Junior Agent could have bypassed the security. We need to find the Shadow Agent before they drink all the sugary glory!
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 | secret badge | writing hand | cap color | favorite snack |
|---|---|---|---|---|---|
| Max | grappling hook | gold gear | right handed | green cap | sour gummies |
| Nancy | decoder ring | silver shield | right handed | blue cap | sour gummies |
| Hardy | grappling hook | ruby laser | right handed | red cap | cheese puffs |
| Jupiter | laser pointer | emerald key | right handed | blue cap | sour gummies |
| Bob | spy camera | ruby laser | left handed | green cap | sour gummies |
| Sam | laser pointer | bronze star | right handed | green cap | sour gummies |
| Nate | grappling hook | silver shield | left handed | blue cap | sour gummies |
| Ben | decoder ring | ruby laser | right handed | blue cap | sour gummies |
| Sally | grappling hook | bronze star | right handed | blue cap | sour gummies |
| Leo | spy camera | ruby laser | left handed | red cap | sour gummies |
| Chloe | decoder ring | gold gear | right handed | green cap | cheese puffs |
| Luke | smoke bomb | gold gear | right handed | red cap | apple slices |
| Zoe | decoder ring | emerald key | right handed | blue cap | sour gummies |
| Toby | smoke bomb | emerald key | right handed | blue cap | apple slices |
| Mia | laser pointer | silver shield | right handed | green cap | sour gummies |
| Maya | grappling hook | bronze star | left handed | blue cap | apple slices |
| Lily | spy camera | emerald key | left handed | blue cap | sour gummies |
| Encyclopedia | smoke bomb | bronze star | right handed | green cap | apple slices |
| Jack | grappling hook | gold gear | left handed | green cap | sour gummies |
| Cam | spy camera | emerald key | right handed | red cap | sour gummies |
| Pete | grappling hook | silver shield | left handed | red cap | sour gummies |
Clue 1
Rounding
Our laser distance radar only shows numbers rounded to the nearest ten. We estimated the escape route to decode this 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.
T
300
5000
40
60
50
400
400
7000
50
900
8000
9000
40
4000
900
9000
T
300
2000
40
7000
800
7000
800
30
90
20
400
7000
4000
40
800
90
7000
8000
500
40
Round 323 to the nearest hundredT
Round 387 to the nearest hundredL
Round 47 to the nearest tenI
Round 88 to the nearest tenB
Round 481 to the nearest hundredG
Round 753 to the nearest hundredR
Round 7,942 to the nearest thousandD
Round 34 to the nearest tenU
Round 58 to the nearest tenV
Round 905 to the nearest hundredN
Round 4,743 to the nearest thousandH
Round 43 to the nearest tenE
Round 3,765 to the nearest thousandS
Round 1,778 to the nearest thousandW
Round 8,913 to the nearest thousandO
Round 19 to the nearest tenY
Round 6,932 to the nearest thousandA
0/17 letters found
Clue 2
Addition
We tallied up all the muddy footprints on the deck. Adding them together gave us the secret lock combination!
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
843
343
931
536
871
246
T
843
582
575
536
889
335
335
343
295
866
575
582
536
689
343
T
843
343
575
871
663
931
663
866
582
536
T
843
931
582
358 + 485 =T
327 + 544 =N
119 + 224 =H
91 + 155 =K
427 + 236 =D
227 + 462 =G
358 + 178 =I
343 + 523 =W
194 + 141 =S
341 + 241 =R
586 + 345 =E
127 + 168 =O
542 + 347 =L
289 + 286 =A
0/14 letters found
Clue 3
Subtraction
The agent dropped a gadget. We subtracted the remaining battery level from the full charge to find the hidden code.
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
699
828
110
306
344
513
818
793
306
344
477
732
344
879
879
319
W
699
477
874
773
773
828
477
793
874
399
399
784
828
793
249
828
513
828
999 - 300 =W
723 - 246 =R
1040 - 161 =M
1129 - 345 =H
536 - 230 =O
591 - 247 =U
178 - 68 =F
1106 - 232 =A
1066 - 238 =E
641 - 242 =T
1069 - 276 =S
876 - 363 =N
404 - 155 =C
865 - 133 =G
474 - 155 =Y
937 - 164 =P
1160 - 342 =D
0/17 letters found
Clue 4
Multiplication facts (1-12)
We found three rows of spy gear boxes. Multiplying the boxes by the rows helped us crack the safe.
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
2
66
120
28
9
99
64
10
7
25
66
30
45
A
2
22
121
45
21
132
A
2
108
A
2
22
27
A
2
66
10
25
121
30
1 × 2 =A
5 × 9 =R
11 × 11 =F
12 × 10 =H
3 × 3 =N
1 × 10 =L
3 × 9 =W
5 × 5 =E
7 × 4 =I
2 × 11 =P
3 × 10 =T
8 × 8 =B
7 × 1 =U
11 × 12 =M
3 × 7 =O
9 × 12 =C
6 × 11 =S
9 × 11 =Y
0/18 letters found
Clue 5
Division facts (1-12) — the last clue
We had to share the secret decoder cards equally among the team. Dividing them up revealed the final message.
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
12 ÷ 4 = ?
56 ÷ 8 = ?
80 ÷ 10 = ?
18 ÷ 3 = ?
60 ÷ 12 = ?
44 ÷ 11 = ?
63 ÷ 7 = ?
84 ÷ 7 = ?
6 ÷ 6 = ?
70 ÷ 7 = ?
16 ÷ 8 = ?
Step 2 — cross out the sentence with each answer
1.The villain hacks the mainframe computer, then leaves behind a muddy footprint.
2.The villain swings across the zipline, then leaves behind a muddy footprint.
3.The villain jumps over the dog gate, then leaves behind a muddy footprint.
4.The villain sneaks past the motion detector, then snaps a secret photo.
5.The villain climbs the rope ladder, then drops a walkie talkie.
6.The villain hacks the mainframe computer, then escapes into the bushes.
7.The villain sneaks past the motion detector, then zips up their backpack.
8.The villain jumps over the dog gate, then zips up their backpack.
9.The villain swings across the zipline, then drops a walkie talkie.
10.The villain climbs the rope ladder, then leaves behind a muddy footprint.
11.The villain swings across the zipline, then escapes into the bushes.
12.The villain climbs the rope ladder, then snaps a secret photo.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Secret Treehouse Caper
Culprit: Sally (grappling hook · bronze star · right handed · blue cap · sour gummies)
- Clue 1 (Rounding): "THE VILLAIN DOES NOT WEAR A RUBY LASER BADGE"Round 323 to the nearest hundred = 300 (T) · Round 387 to the nearest hundred = 400 (L) · Round 47 to the nearest ten = 50 (I) · Round 88 to the nearest ten = 90 (B) · Round 481 to the nearest hundred = 500 (G) · Round 753 to the nearest hundred = 800 (R) · Round 7,942 to the nearest thousand = 8000 (D) · Round 34 to the nearest ten = 30 (U) · Round 58 to the nearest ten = 60 (V) · Round 905 to the nearest hundred = 900 (N) · Round 4,743 to the nearest thousand = 5000 (H) · Round 43 to the nearest ten = 40 (E) · Round 3,765 to the nearest thousand = 4000 (S) · Round 1,778 to the nearest thousand = 2000 (W) · Round 8,913 to the nearest thousand = 9000 (O) · Round 19 to the nearest ten = 20 (Y) · Round 6,932 to the nearest thousand = 7000 (A)
- Clue 2 (Addition): "THE INK TRAILS SHOW A RIGHT HANDED WRITER"358 + 485 = 843 (T) · 327 + 544 = 871 (N) · 119 + 224 = 343 (H) · 91 + 155 = 246 (K) · 427 + 236 = 663 (D) · 227 + 462 = 689 (G) · 358 + 178 = 536 (I) · 343 + 523 = 866 (W) · 194 + 141 = 335 (S) · 341 + 241 = 582 (R) · 586 + 345 = 931 (E) · 127 + 168 = 295 (O) · 542 + 347 = 889 (L) · 289 + 286 = 575 (A)
- Clue 3 (Subtraction): "WE FOUND SOUR GUMMY WRAPPERS AT THE SCENE"999 - 300 = 699 (W) · 723 - 246 = 477 (R) · 1040 - 161 = 879 (M) · 1129 - 345 = 784 (H) · 536 - 230 = 306 (O) · 591 - 247 = 344 (U) · 178 - 68 = 110 (F) · 1106 - 232 = 874 (A) · 1066 - 238 = 828 (E) · 641 - 242 = 399 (T) · 1069 - 276 = 793 (S) · 876 - 363 = 513 (N) · 404 - 155 = 249 (C) · 865 - 133 = 732 (G) · 474 - 155 = 319 (Y) · 937 - 164 = 773 (P) · 1160 - 342 = 818 (D)
- Clue 4 (Multiplication facts (1-12)): "A SHINY BLUE STRAP FROM A CAP WAS LEFT"1 × 2 = 2 (A) · 5 × 9 = 45 (R) · 11 × 11 = 121 (F) · 12 × 10 = 120 (H) · 3 × 3 = 9 (N) · 1 × 10 = 10 (L) · 3 × 9 = 27 (W) · 5 × 5 = 25 (E) · 7 × 4 = 28 (I) · 2 × 11 = 22 (P) · 3 × 10 = 30 (T) · 8 × 8 = 64 (B) · 7 × 1 = 7 (U) · 11 × 12 = 132 (M) · 3 × 7 = 21 (O) · 9 × 12 = 108 (C) · 6 × 11 = 66 (S) · 9 × 11 = 99 (Y)
- Clue 5 (Division facts (1-12)): surviving statement (box 11) → Sally12 ÷ 4 = 3 · 56 ÷ 8 = 7 · 80 ÷ 10 = 8 · 18 ÷ 3 = 6 · 60 ÷ 12 = 5 · 44 ÷ 11 = 4 · 63 ÷ 7 = 9 · 84 ÷ 7 = 12 · 6 ÷ 6 = 1 · 70 ÷ 7 = 10 · 16 ÷ 8 = 2
About this mystery
- Grade level
- Grade 3 math
- Math topics
- Rounding, Addition, Subtraction, Multiplication, Division
- Reading level
- grades 3-4
- Theme
- The Secret Treehouse Caper — set in Clubhouse Sector Seven and the giant backyard oak tree
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects