Grade 2Reading: grades 1-2AdditionPlace valueSubtractionSkip countingMissing addends
The Great Treehouse Mystery
Someone took the Golden Treehouse Trophy right before the big club meeting! The Treehouse Club needs your help to find the sneaky thief and get the trophy back.
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 | Secret Tool | Club Badge | Writing Hand | Costume Fiber | Secret Weakness |
|---|---|---|---|---|---|
| Leo | bubble launcher | gold star badge | writes right handed | blue yarn fuzz | scared of frogs |
| Kai | glide wings | silver compass badge | writes right handed | green yarn fuzz | ticklish on toes |
| Eli | spy walkie | gold star badge | writes right handed | red yarn fuzz | ticklish on toes |
| Amy | bubble launcher | gold star badge | writes right handed | blue yarn fuzz | hates cold water |
| Fay | bubble launcher | silver compass badge | writes left handed | blue yarn fuzz | ticklish on toes |
| Mae | bubble launcher | silver compass badge | writes left handed | blue yarn fuzz | scared of frogs |
| Gus | grappling hook | bronze binocular badge | writes right handed | red yarn fuzz | hates cold water |
| Ted | laser flashlight | blue anchor badge | writes left handed | blue yarn fuzz | hates cold water |
| Hal | laser flashlight | bronze binocular badge | writes right handed | blue yarn fuzz | scared of frogs |
| Ivy | grappling hook | blue anchor badge | writes right handed | blue yarn fuzz | scared of frogs |
| Rex | spy walkie | silver compass badge | writes left handed | green yarn fuzz | scared of frogs |
| Meg | grappling hook | silver compass badge | writes right handed | green yarn fuzz | hates cold water |
| Art | bubble launcher | green ranger badge | writes right handed | blue yarn fuzz | scared of frogs |
| Dan | grappling hook | silver compass badge | writes right handed | red yarn fuzz | scared of frogs |
| Sam | laser flashlight | blue anchor badge | writes right handed | blue yarn fuzz | hates cold water |
| Mia | bubble launcher | silver compass badge | writes right handed | blue yarn fuzz | scared of frogs |
| Joy | spy walkie | gold star badge | writes right handed | red yarn fuzz | scared of frogs |
| Eva | spy walkie | bronze binocular badge | writes left handed | blue yarn fuzz | scared of frogs |
| Ned | laser flashlight | bronze binocular badge | writes right handed | blue yarn fuzz | ticklish on toes |
| Zoe | laser flashlight | bronze binocular badge | writes left handed | red yarn fuzz | ticklish on toes |
| Max | laser flashlight | blue anchor badge | writes left handed | red yarn fuzz | scared of frogs |
Clue 1
Addition
We found two piles of muddy footprints by the slide. Let us add the big prints and the small prints to see how many there are in 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
52
55
73
T
52
55
81
73
41
64
50
73
97
54
50
T
52
42
73
71
69
71
43
69
73
73
54
69
71
54
43
73
69
83
71
64
43
73
22 + 30 =T
24 + 31 =H
15 + 35 =O
20 + 44 =D
32 + 37 =R
19 + 24 =G
18 + 23 =F
19 + 35 =N
39 + 34 =E
47 + 36 =B
57 + 24 =I
56 + 41 =S
30 + 12 =W
50 + 21 =A
0/14 letters found
Clue 2
Place value
The lock on the gear box needs a secret code. Look at the tens and ones blocks on the note to find the right 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
83
79
T
41
83
28
79
11
13
46
23
T
41
79
56
86
23
T
41
79
13
28
T
41
83
T
41
83
79
28
46
46
28
89
83
T
41
83
56
86
75
What number has 4 tens and 1 one?T
What number has 7 tens and 5 ones?D
What number has 2 tens and 8 ones?I
What number has 8 tens and 3 ones?H
What number has 1 ten and 1 one?F
What number has 8 tens and 6 ones?N
What number has 4 tens and 6 ones?R
What number has 8 tens and 9 ones?G
What number has 1 ten and 3 ones?W
What number has 7 tens and 9 ones?E
What number has 5 tens and 6 ones?A
What number has 2 tens and 3 ones?O
0/12 letters found
Clue 3
Subtraction
Some of our snack boxes are missing from the cooler. We had ten but now we have less. Subtract to find how many the thief 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
60
41
72
T
60
41
81
72
30
58
40
26
40
82
40
65
82
41
72
26
40
29
58
72
72
26
30
58
68
29
14
66
23
17
72
56
89 - 29 =T
45 - 31 =J
75 - 17 =R
51 - 34 =P
42 - 2 =A
60 - 34 =N
96 - 28 =O
70 - 40 =F
120 - 38 =W
106 - 34 =E
60 - 4 =D
62 - 39 =M
99 - 34 =Y
84 - 18 =U
58 - 17 =H
101 - 20 =I
62 - 33 =G
0/17 letters found
Clue 4
Skip counting
The thief climbed the giant oak tree by skipping steps. Skip count the numbers on the branches to follow their 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.
B
20
15
80
45
16
14
28
21
55
80
60
60
130
14
18
18
10
80
90
140
10
50
10
27
45
15
14
42
42
45
28
Skip-count by 5s. Fill the blank: 5, 10, 15, ___, 25, 30B
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, ___, 60, 65F
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, ___, 30, 32R
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, ___, 70, 80Z
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, ___, 12, 14T
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, ___, 24, 27N
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, ___, 18, 21L
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, ___, 100, 110C
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, ___, 50, 55E
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, ___, 140, 150W
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, ___, 30, 33H
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, ___, 45, 48D
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, ___, 60, 70O
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, ___, 18, 20Y
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, ___, 150, 160K
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, ___, 20, 22S
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, ___, 16, 18A
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, ___, 90, 100U
0/18 letters found
Clue 5
Missing addends — the last clue
We need eight shiny club keys to open the big map case. We only have five. How many more keys do we need to find?
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
6 + ___ = 18
7 + ___ = 11
8 + ___ = 10
5 + ___ = 16
6 + ___ = 11
3 + ___ = 6
10 + ___ = 16
3 + ___ = 10
2 + ___ = 11
3 + ___ = 4
7 + ___ = 15
Step 2 — cross out the sentence with each answer
1.The villain zips down the backyard slide, then grabs the secret map of the park.
2.The villain climbs up the wooden ladder, then steals the fancy walkie talkies.
3.The villain swings on a thick rope, then takes the box of chocolate cookies.
4.The villain swings on a thick rope, then pockets the club rulebook.
5.The villain zips down the backyard slide, then steals the fancy walkie talkies.
6.The villain climbs up the wooden ladder, then pockets the club rulebook.
7.The villain crawls through the secret hatch, then pockets the club rulebook.
8.The villain crawls through the secret hatch, then steals the fancy walkie talkies.
9.The villain sneaks past the sleeping dog, then steals the fancy walkie talkies.
10.The villain sneaks past the sleeping dog, then grabs the secret map of the park.
11.The villain zips down the backyard slide, then pockets the club rulebook.
12.The villain sneaks past the sleeping dog, then snatches the shining golden trophy.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Great Treehouse Mystery
Culprit: Mia (bubble launcher · silver compass badge · writes right handed · blue yarn fuzz · scared of frogs)
- Clue 1 (Addition): "THE THIEF DOES NOT WEAR A GREEN RANGER BADGE"22 + 30 = 52 (T) · 24 + 31 = 55 (H) · 15 + 35 = 50 (O) · 20 + 44 = 64 (D) · 32 + 37 = 69 (R) · 19 + 24 = 43 (G) · 18 + 23 = 41 (F) · 19 + 35 = 54 (N) · 39 + 34 = 73 (E) · 47 + 36 = 83 (B) · 57 + 24 = 81 (I) · 56 + 41 = 97 (S) · 30 + 12 = 42 (W) · 50 + 21 = 71 (A)
- Clue 2 (Place value): "THE THIEF WROTE A NOTE WITH THEIR RIGHT HAND"What number has 4 tens and 1 one? = 41 (T) · What number has 7 tens and 5 ones? = 75 (D) · What number has 2 tens and 8 ones? = 28 (I) · What number has 8 tens and 3 ones? = 83 (H) · What number has 1 ten and 1 one? = 11 (F) · What number has 8 tens and 6 ones? = 86 (N) · What number has 4 tens and 6 ones? = 46 (R) · What number has 8 tens and 9 ones? = 89 (G) · What number has 1 ten and 3 ones? = 13 (W) · What number has 7 tens and 9 ones? = 79 (E) · What number has 5 tens and 6 ones? = 56 (A) · What number has 2 tens and 3 ones? = 23 (O)
- Clue 3 (Subtraction): "THE THIEF RAN AWAY WHEN A GREEN FROG JUMPED"89 - 29 = 60 (T) · 45 - 31 = 14 (J) · 75 - 17 = 58 (R) · 51 - 34 = 17 (P) · 42 - 2 = 40 (A) · 60 - 34 = 26 (N) · 96 - 28 = 68 (O) · 70 - 40 = 30 (F) · 120 - 38 = 82 (W) · 106 - 34 = 72 (E) · 60 - 4 = 56 (D) · 62 - 39 = 23 (M) · 99 - 34 = 65 (Y) · 84 - 18 = 66 (U) · 58 - 17 = 41 (H) · 101 - 20 = 81 (I) · 62 - 33 = 29 (G)
- Clue 4 (Skip counting): "BLUE YARN FUZZ WAS STUCK TO THE LADDER"Skip-count by 5s. Fill the blank: 5, 10, 15, ___, 25, 30 = 20 (B) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, ___, 60, 65 = 55 (F) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, ___, 30, 32 = 28 (R) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, ___, 70, 80 = 60 (Z) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, ___, 12, 14 = 10 (T) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, ___, 24, 27 = 21 (N) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, ___, 18, 21 = 15 (L) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, ___, 100, 110 = 90 (C) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, ___, 50, 55 = 45 (E) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, ___, 140, 150 = 130 (W) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, ___, 30, 33 = 27 (H) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, ___, 45, 48 = 42 (D) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, ___, 60, 70 = 50 (O) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, ___, 18, 20 = 16 (Y) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, ___, 150, 160 = 140 (K) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, ___, 20, 22 = 18 (S) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, ___, 16, 18 = 14 (A) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, ___, 90, 100 = 80 (U)
- Clue 5 (Missing addends): surviving statement (box 10) → Mia6 + ___ = 18 = 12 · 7 + ___ = 11 = 4 · 8 + ___ = 10 = 2 · 5 + ___ = 16 = 11 · 6 + ___ = 11 = 5 · 3 + ___ = 6 = 3 · 10 + ___ = 16 = 6 · 3 + ___ = 10 = 7 · 2 + ___ = 11 = 9 · 3 + ___ = 4 = 1 · 7 + ___ = 15 = 8
About this mystery
- Grade level
- Grade 2 math
- Math topics
- Addition, Place value, Subtraction, Skip counting, Missing addends
- Reading level
- grades 1-2
- Theme
- The Great Treehouse Mystery — set in Oak Tree Park
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects