Grade 2Reading: grades 1-2Place valueAdditionSubtractionSkip countingMissing addends
The Great Treehouse Mystery
Someone took the Golden Compass from our secret treehouse! We must follow the trail, solve the clues, and find the sneaky Prankster before the sun goes down. Ready, team? Let us solve this mystery!
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 | Explorer Skill | Special Talent | Writing Hand | Hair Color | Biggest Fear |
|---|---|---|---|---|---|
| Emma | map reader | tent builder | right handed | black hair | scared of bugs |
| Rex | tree climber | berry finder | right handed | blonde hair | scared of frogs |
| Zoe | map reader | star gazer | left handed | brown hair | scared of bugs |
| Leo | night watcher | berry finder | left handed | blonde hair | scared of frogs |
| Jake | night watcher | bridge maker | right handed | blonde hair | scared of mud |
| Zack | trail runner | star gazer | right handed | black hair | scared of mud |
| Max | tree climber | berry finder | right handed | brown hair | scared of frogs |
| Abby | map reader | tent builder | left handed | blonde hair | scared of mud |
| Ruby | tree climber | animal caller | right handed | blonde hair | scared of frogs |
| Nora | tree climber | berry finder | left handed | blonde hair | scared of bugs |
| Eli | trail runner | animal caller | right handed | brown hair | scared of bugs |
| Dan | trail runner | berry finder | right handed | blonde hair | scared of frogs |
| Toby | tree climber | bridge maker | right handed | blonde hair | scared of mud |
| Cole | tree climber | star gazer | left handed | black hair | scared of mud |
| Ben | trail runner | star gazer | right handed | brown hair | scared of mud |
| Amy | map reader | star gazer | right handed | black hair | scared of mud |
| Luke | trail runner | bridge maker | right handed | blonde hair | scared of frogs |
| Finn | rope glider | star gazer | right handed | black hair | scared of frogs |
| Ava | rope glider | tent builder | left handed | black hair | scared of frogs |
| Lily | trail runner | tent builder | right handed | blonde hair | scared of frogs |
| Mia | map reader | bridge maker | right handed | brown hair | scared of frogs |
Clue 1
Place value
We found a wooden safe. It has digit keys for tens and ones. Count the base ten blocks to unlock it.
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
40
32
85
99
61
50
88
57
77
T
40
85
61
62
50
88
88
76
T
40
42
35
65
58
24
T
40
85
88
T
40
77
What number has 4 tens and 0 ones?T
What number has 6 tens and 2 ones?C
What number has 7 tens and 7 ones?S
What number has 9 tens and 9 ones?P
What number has 3 tens and 2 ones?H
What number has 5 tens and 8 ones?L
What number has 3 tens and 5 ones?U
What number has 6 tens and 1 one?R
What number has 2 tens and 4 ones?D
What number has 8 tens and 8 ones?N
What number has 5 tens and 7 ones?K
What number has 8 tens and 5 ones?E
What number has 7 tens and 6 ones?O
What number has 4 tens and 2 ones?B
What number has 5 tens and 0 ones?A
What number has 6 tens and 5 ones?I
0/16 letters found
Clue 2
Addition
We must pack our gear. We put some flashlights and rope in our bags. Add them up to get the total.
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
94
71
76
53
78
51
76
61
89
76
70
76
55
80
51
30
36
80
30
T
94
71
76
70
97
28
71
T
94
61
97
36
76
33 + 61 =T
28 + 42 =R
26 + 27 =C
46 + 30 =E
38 + 17 =F
13 + 17 =N
26 + 54 =O
59 + 30 =W
15 + 21 =D
27 + 34 =S
36 + 42 =L
42 + 29 =H
30 + 67 =I
27 + 24 =U
16 + 12 =G
0/15 letters found
Clue 3
Subtraction
The thief took some items. We had ten maps but some are gone. Subtract to find the missing maps.
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
83
37
39
31
40
79
23
39
13
31
65
27
13
14
32
12
16
79
37
14
13
27
15
37
37
16
32
14
67
37
119 - 36 =W
28 - 1 =T
60 - 21 =F
37 - 6 =O
47 - 34 =R
27 - 13 =A
39 - 27 =K
46 - 14 =C
28 - 13 =H
46 - 9 =E
69 - 2 =P
82 - 3 =N
17 - 1 =S
101 - 36 =G
66 - 26 =U
48 - 25 =D
0/16 letters found
Clue 4
Skip counting
The wooden path has steps. We must jump by twos to stay safe. Skip count to the end of 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.
A
12
35
33
55
140
110
39
35
50
36
45
9
100
65
39
33
A
12
45
9
25
A
12
65
36
45
39
110
100
30
100
20
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, ___, 14, 16A
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, ___, 30, 35W
Skip-count by 10s. Fill the blank: 10, 20, ___, 40, 50K
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, ___, 120, 130H
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, ___, 150, 160G
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, ___, 42, 45T
Skip-count by 3s. Fill the blank: 3, 6, ___, 12, 15D
Skip-count by 5s. Fill the blank: 5, 10, 15, ___, 25, 30Y
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, ___, 70, 75S
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, ___, 110, 120E
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, ___, 36, 39R
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, ___, 60, 70L
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, ___, 40, 45B
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, ___, 50, 55N
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, ___, 39, 42O
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, ___, 60, 65I
0/16 letters found
Clue 5
Missing addends — the last clue
We want to build a bridge. We need ten logs. We have six logs now. How many more do we need?
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
10 + ___ = 11
10 + ___ = 16
7 + ___ = 12
6 + ___ = 9
6 + ___ = 14
2 + ___ = 14
5 + ___ = 7
2 + ___ = 12
9 + ___ = 20
10 + ___ = 19
4 + ___ = 8
Step 2 — cross out the sentence with each answer
1.The villain dashes through the bushes, then gathers sweet wild berries.
2.The villain climbs the big oak tree, then sets up a small camp.
3.The villain watches the dark trail, then crosses the wooden bridge.
4.The villain dashes through the bushes, then sets up a small camp.
5.The villain dashes through the bushes, then crosses the wooden bridge.
6.The villain climbs the big oak tree, then gathers sweet wild berries.
7.The villain climbs the big oak tree, then makes a loud bird call.
8.The villain checks the old trail map, then points up at the big dipper.
9.The villain zips down the rope, then gathers sweet wild berries.
10.The villain watches the dark trail, then points up at the big dipper.
11.The villain checks the old trail map, then sets up a small camp.
12.The villain watches the dark trail, then makes a loud bird call.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Great Treehouse Mystery
Culprit: Ruby (tree climber · animal caller · right handed · blonde hair · scared of frogs)
- Clue 1 (Place value): "THE PRANKSTER CANNOT BUILD TENTS"What number has 4 tens and 0 ones? = 40 (T) · What number has 6 tens and 2 ones? = 62 (C) · What number has 7 tens and 7 ones? = 77 (S) · What number has 9 tens and 9 ones? = 99 (P) · What number has 3 tens and 2 ones? = 32 (H) · What number has 5 tens and 8 ones? = 58 (L) · What number has 3 tens and 5 ones? = 35 (U) · What number has 6 tens and 1 one? = 61 (R) · What number has 2 tens and 4 ones? = 24 (D) · What number has 8 tens and 8 ones? = 88 (N) · What number has 5 tens and 7 ones? = 57 (K) · What number has 8 tens and 5 ones? = 85 (E) · What number has 7 tens and 6 ones? = 76 (O) · What number has 4 tens and 2 ones? = 42 (B) · What number has 5 tens and 0 ones? = 50 (A) · What number has 6 tens and 5 ones? = 65 (I)
- Clue 2 (Addition): "THE CLUES WERE FOUND ON THE RIGHT SIDE"33 + 61 = 94 (T) · 28 + 42 = 70 (R) · 26 + 27 = 53 (C) · 46 + 30 = 76 (E) · 38 + 17 = 55 (F) · 13 + 17 = 30 (N) · 26 + 54 = 80 (O) · 59 + 30 = 89 (W) · 15 + 21 = 36 (D) · 27 + 34 = 61 (S) · 36 + 42 = 78 (L) · 42 + 29 = 71 (H) · 30 + 67 = 97 (I) · 27 + 24 = 51 (U) · 16 + 12 = 28 (G)
- Clue 3 (Subtraction): "WE FOUND FROG TRACKS NEAR THE ESCAPE"119 - 36 = 83 (W) · 28 - 1 = 27 (T) · 60 - 21 = 39 (F) · 37 - 6 = 31 (O) · 47 - 34 = 13 (R) · 27 - 13 = 14 (A) · 39 - 27 = 12 (K) · 46 - 14 = 32 (C) · 28 - 13 = 15 (H) · 46 - 9 = 37 (E) · 69 - 2 = 67 (P) · 82 - 3 = 79 (N) · 17 - 1 = 16 (S) · 101 - 36 = 65 (G) · 66 - 26 = 40 (U) · 48 - 25 = 23 (D)
- Clue 4 (Skip counting): "A BRIGHT BLONDE STRAND WAS ON THE KEY"Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, ___, 14, 16 = 12 (A) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, ___, 30, 35 = 25 (W) · Skip-count by 10s. Fill the blank: 10, 20, ___, 40, 50 = 30 (K) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, ___, 120, 130 = 110 (H) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, ___, 150, 160 = 140 (G) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, ___, 42, 45 = 39 (T) · Skip-count by 3s. Fill the blank: 3, 6, ___, 12, 15 = 9 (D) · Skip-count by 5s. Fill the blank: 5, 10, 15, ___, 25, 30 = 20 (Y) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, ___, 70, 75 = 65 (S) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, ___, 110, 120 = 100 (E) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, ___, 36, 39 = 33 (R) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, ___, 60, 70 = 50 (L) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, ___, 40, 45 = 35 (B) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, ___, 50, 55 = 45 (N) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, ___, 39, 42 = 36 (O) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, ___, 60, 65 = 55 (I)
- Clue 5 (Missing addends): surviving statement (box 7) → Ruby10 + ___ = 11 = 1 · 10 + ___ = 16 = 6 · 7 + ___ = 12 = 5 · 6 + ___ = 9 = 3 · 6 + ___ = 14 = 8 · 2 + ___ = 14 = 12 · 5 + ___ = 7 = 2 · 2 + ___ = 12 = 10 · 9 + ___ = 20 = 11 · 10 + ___ = 19 = 9 · 4 + ___ = 8 = 4
About this mystery
- Grade level
- Grade 2 math
- Math topics
- Place value, Addition, Subtraction, Skip counting, Missing addends
- Reading level
- grades 1-2
- Theme
- The Great Treehouse Mystery — set in The Whispering Woods
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects