Grade 2Reading: grades 1-2Place valueAdditionSubtractionSkip countingMissing addends
The Great Treehouse Mystery
The gold map is gone from the treehouse! A sneaky club member took it. We need to find the thief before they dig up the secret club chest.
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 | Main Tool | Escape Gear | Writing Hand | Hair Color | Secret Fear |
|---|---|---|---|---|---|
| Cole | rope lasso | wind glider | right handed | purple hair | squeaky toy |
| Jack | walkie talkie | spring shoes | right handed | green hair | cookie crumbs |
| Ella | rope lasso | fast bike | left handed | orange hair | cookie crumbs |
| Zoe | flash light | hover board | right handed | purple hair | cookie crumbs |
| Ryan | rope lasso | hover board | left handed | green hair | cookie crumbs |
| Cora | flash light | spring shoes | right handed | orange hair | squeaky toy |
| Ben | laser beam | jet pack | right handed | orange hair | cookie crumbs |
| Mia | bubble blast | hover board | right handed | orange hair | squeaky toy |
| Toby | rope lasso | hover board | right handed | orange hair | squeaky toy |
| Ruby | bubble blast | jet pack | right handed | orange hair | cookie crumbs |
| Zack | rope lasso | hover board | right handed | orange hair | cookie crumbs |
| Luke | laser beam | fast bike | left handed | green hair | cookie crumbs |
| Annie | bubble blast | jet pack | right handed | orange hair | squeaky toy |
| Sam | walkie talkie | jet pack | right handed | purple hair | cookie crumbs |
| Owen | laser beam | fast bike | left handed | orange hair | squeaky toy |
| Lily | bubble blast | wind glider | right handed | orange hair | squeaky toy |
| Leo | bubble blast | hover board | left handed | orange hair | squeaky toy |
| Max | bubble blast | wind glider | right handed | green hair | squeaky toy |
| Finn | flash light | hover board | right handed | orange hair | water spray |
| Abby | flash light | wind glider | left handed | purple hair | water spray |
| Noah | rope lasso | wind glider | left handed | orange hair | water spray |
Clue 1
Place value
The thief left a note with a secret code. We must look at the tens and ones blocks to read the map room number.
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
41
68
89
44
17
22
84
22
T
41
68
51
95
89
83
29
40
38
84
43
83
68
22
89
83
What number has 4 tens and 1 one?T
What number has 6 tens and 8 ones?H
What number has 8 tens and 9 ones?E
What number has 4 tens and 0 ones?R
What number has 1 ten and 7 ones?D
What number has 5 tens and 1 one?A
What number has 8 tens and 3 ones?S
What number has 4 tens and 4 ones?Y
What number has 9 tens and 5 ones?V
What number has 8 tens and 4 ones?N
What number has 2 tens and 9 ones?P
What number has 2 tens and 2 ones?O
What number has 3 tens and 8 ones?I
What number has 4 tens and 3 ones?G
0/14 letters found
Clue 2
Addition
We found some dropped gear in the grass. Let us add up all the shiny badges to find the path they took.
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
33
91
50
67
49
32
94
T
40
56
63
91
32
T
40
33
91
94
89
89
94
25
33
T
40
33
67
49
32
12 + 28 =T
45 + 22 =A
32 + 59 =E
15 + 10 =G
34 + 60 =I
19 + 30 =N
13 + 19 =D
34 + 55 =R
44 + 19 =S
23 + 10 =H
18 + 32 =B
34 + 22 =U
0/12 letters found
Clue 3
Subtraction
There are footprints near the treehouse. Subtract the small prints from the big ones to count how many steps they made.
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
15
77
63
35
16
49
74
49
33
49
35
67
16
17
20
49
29
40
51
63
49
38
35
T
15
17
35
18 - 3 =T
49 - 14 =Y
86 - 9 =H
108 - 34 =N
73 - 33 =Q
49 - 32 =O
75 - 37 =K
31 - 11 =M
47 - 14 =W
98 - 31 =F
66 - 3 =E
61 - 12 =A
52 - 36 =R
88 - 37 =U
55 - 26 =S
0/15 letters found
Clue 4
Skip counting
The path goes past the stepping stones. We need to skip count by fives on the wet rocks to follow the trail.
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
10
60
26
140
15
12
24
25
140
28
140
15
90
60
24
140
90
50
12
21
60
40
50
20
90
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, ___, 12, 14W
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, ___, 14, 16N
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, ___, 24, 27G
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, ___, 30, 35C
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, ___, 30, 32L
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, ___, 150, 160O
Skip-count by 10s. Fill the blank: 10, 20, 30, ___, 50, 60H
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, ___, 100, 110R
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, ___, 26, 28D
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, ___, 65, 70E
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, ___, 18, 21U
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, ___, 22, 24I
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, ___, 28, 30F
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, ___, 55, 60A
0/14 letters found
Clue 5
Missing addends — the last clue
We have some old keys but we need more to open the chest. Find the missing number of keys we need to collect.
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 + ___ = 5
9 + ___ = 17
9 + ___ = 18
7 + ___ = 17
9 + ___ = 20
9 + ___ = 16
3 + ___ = 15
8 + ___ = 11
4 + ___ = 10
9 + ___ = 11
10 + ___ = 15
Step 2 — cross out the sentence with each answer
1.The villain shoots a bubble blast, then flies off on a wind glider.
2.The villain talks on a walkie talkie, then flies off on a wind glider.
3.The villain shines a laser beam, then skates away on a hover board.
4.The villain throws a rope lasso, then skates away on a hover board.
5.The villain throws a rope lasso, then bounces high on spring shoes.
6.The villain turns on a flash light, then flies off on a wind glider.
7.The villain shines a laser beam, then zooms off on a jet pack.
8.The villain shoots a bubble blast, then skates away on a hover board.
9.The villain shoots a bubble blast, then zooms off on a jet pack.
10.The villain turns on a flash light, then zooms off on a jet pack.
11.The villain turns on a flash light, then rides away on a fast bike.
12.The villain throws a rope lasso, then zooms off on a jet pack.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Great Treehouse Mystery
Culprit: Lily (bubble blast · wind glider · right handed · orange hair · squeaky toy)
- Clue 1 (Place value): "THEY DO NOT HAVE SPRING SHOES"What number has 4 tens and 1 one? = 41 (T) · What number has 6 tens and 8 ones? = 68 (H) · What number has 8 tens and 9 ones? = 89 (E) · What number has 4 tens and 0 ones? = 40 (R) · What number has 1 ten and 7 ones? = 17 (D) · What number has 5 tens and 1 one? = 51 (A) · What number has 8 tens and 3 ones? = 83 (S) · What number has 4 tens and 4 ones? = 44 (Y) · What number has 9 tens and 5 ones? = 95 (V) · What number has 8 tens and 4 ones? = 84 (N) · What number has 2 tens and 9 ones? = 29 (P) · What number has 2 tens and 2 ones? = 22 (O) · What number has 3 tens and 8 ones? = 38 (I) · What number has 4 tens and 3 ones? = 43 (G)
- Clue 2 (Addition): "THE BANDIT USED THEIR RIGHT HAND"12 + 28 = 40 (T) · 45 + 22 = 67 (A) · 32 + 59 = 91 (E) · 15 + 10 = 25 (G) · 34 + 60 = 94 (I) · 19 + 30 = 49 (N) · 13 + 19 = 32 (D) · 34 + 55 = 89 (R) · 44 + 19 = 63 (S) · 23 + 10 = 33 (H) · 18 + 32 = 50 (B) · 34 + 22 = 56 (U)
- Clue 3 (Subtraction): "THEY RAN AWAY FROM A SQUEAKY TOY"18 - 3 = 15 (T) · 49 - 14 = 35 (Y) · 86 - 9 = 77 (H) · 108 - 34 = 74 (N) · 73 - 33 = 40 (Q) · 49 - 32 = 17 (O) · 75 - 37 = 38 (K) · 31 - 11 = 20 (M) · 47 - 14 = 33 (W) · 98 - 31 = 67 (F) · 66 - 3 = 63 (E) · 61 - 12 = 49 (A) · 52 - 36 = 16 (R) · 88 - 37 = 51 (U) · 55 - 26 = 29 (S)
- Clue 4 (Skip counting): "WE FOUND COLOURED ORANGE HAIR"Skip-count by 2s. Fill the blank: 2, 4, 6, 8, ___, 12, 14 = 10 (W) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, ___, 14, 16 = 12 (N) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, ___, 24, 27 = 21 (G) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, ___, 30, 35 = 25 (C) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, ___, 30, 32 = 28 (L) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, ___, 150, 160 = 140 (O) · Skip-count by 10s. Fill the blank: 10, 20, 30, ___, 50, 60 = 40 (H) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, ___, 100, 110 = 90 (R) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, ___, 26, 28 = 24 (D) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, ___, 65, 70 = 60 (E) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, ___, 18, 21 = 15 (U) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, ___, 22, 24 = 20 (I) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, ___, 28, 30 = 26 (F) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, ___, 55, 60 = 50 (A)
- Clue 5 (Missing addends): surviving statement (box 1) → Lily1 + ___ = 5 = 4 · 9 + ___ = 17 = 8 · 9 + ___ = 18 = 9 · 7 + ___ = 17 = 10 · 9 + ___ = 20 = 11 · 9 + ___ = 16 = 7 · 3 + ___ = 15 = 12 · 8 + ___ = 11 = 3 · 4 + ___ = 10 = 6 · 9 + ___ = 11 = 2 · 10 + ___ = 15 = 5
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 Green Valley Treehouse
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects