🔎 HistoryGrade 2Reading: grades 1-2SubtractionAdditionPlace valueSkip countingMissing addends
The Museum of Yesterday Mystery
Oh no! A sneaky Time Thief broke into the Museum of Yesterday and hid the golden dinosaur bone! The Head Curator needs your help. Use your math skills to find the thief before the museum opens!
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 | Time Gadget | Museum Badge | Writing Hand | Wig Style | Loud Sound |
|---|---|---|---|---|---|
| Clara | pocket sundial | wax seal | left handed | curly brown wig | train whistle |
| Ludwig | spy glass | feather quill | left handed | braided black wig | train whistle |
| Marie | pocket sundial | silver coin | right handed | curly brown wig | steamboat horn |
| Betsy | iron key | feather quill | right handed | curly brown wig | train whistle |
| Susan | brass compass | feather quill | right handed | curly brown wig | train whistle |
| Vincent | brass compass | wax seal | right handed | powdered white wig | clanging bell |
| Cleo | brass compass | silver coin | right handed | curly brown wig | train whistle |
| Joan | sand timer | silver coin | right handed | powdered white wig | train whistle |
| Florence | spy glass | wax seal | left handed | braided black wig | steamboat horn |
| Harriet | spy glass | gold crown | right handed | powdered white wig | train whistle |
| Eleanor | iron key | feather quill | left handed | braided black wig | clanging bell |
| George | iron key | wax seal | left handed | curly brown wig | train whistle |
| Rosa | spy glass | wax seal | right handed | powdered white wig | train whistle |
| Amelia | brass compass | feather quill | left handed | braided black wig | steamboat horn |
| Ben | brass compass | silver coin | right handed | curly brown wig | clanging bell |
| Abe | spy glass | scroll map | right handed | curly brown wig | steamboat horn |
| Thomas | iron key | silver coin | left handed | curly brown wig | train whistle |
| Albert | spy glass | wax seal | left handed | powdered white wig | train whistle |
| Leonardo | sand timer | gold crown | right handed | curly brown wig | train whistle |
| Booker | pocket sundial | feather quill | right handed | curly brown wig | train whistle |
| Jane | iron key | gold crown | right handed | braided black wig | steamboat horn |
Clue 1
Subtraction
The curator had ten old maps on the wall but some fell down. We subtract the ones on the floor to see how many are left. This tells us about the thief's badge!
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
31
42
33
T
31
42
61
33
78
54
39
33
52
57
39
T
31
42
21
65
33
21
56
39
45
54
46
74
39
26
57
39 - 8 =T
48 - 15 =E
105 - 31 =R
42 - 16 =W
108 - 30 =F
92 - 38 =D
69 - 23 =C
44 - 5 =O
61 - 4 =N
89 - 24 =V
75 - 23 =S
38 - 17 =A
59 - 14 =L
96 - 35 =I
71 - 29 =H
69 - 13 =G
0/16 letters found
Clue 2
Addition
A guard found a pile of old coins in the hall. Then they found another pile. We can add them up to learn how the thief writes!
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
59
95
83
61
64
61
43
83
70
T
59
96
28
45
T
59
83
96
29
T
59
95
T
59
95
83
29
28
28
29
41
95
T
59
95
55
78
22
41 + 18 =T
9 + 20 =I
44 + 52 =W
25 + 18 =P
43 + 52 =H
29 + 49 =N
33 + 50 =E
24 + 37 =S
9 + 13 =D
26 + 19 =O
20 + 8 =R
40 + 24 =U
28 + 42 =C
22 + 19 =G
29 + 26 =A
0/15 letters found
Clue 3
Place value
The thief left a code on a digital clock. We need to look at the tens and ones to find the secret number. This tells us what scared the thief!
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
59
61
58
67
98
58
72
58
63
46
26
72
58
14
97
32
T
59
61
58
T
59
72
26
54
38
98
61
54
63
T
59
82
58
What number has 5 tens and 9 ones?T
What number has 4 tens and 6 ones?C
What number has 6 tens and 1 one?H
What number has 3 tens and 2 ones?F
What number has 6 tens and 7 ones?Y
What number has 5 tens and 8 ones?E
What number has 1 ten and 4 ones?D
What number has 6 tens and 3 ones?S
What number has 9 tens and 8 ones?W
What number has 3 tens and 8 ones?N
What number has 9 tens and 7 ones?O
What number has 5 tens and 4 ones?I
What number has 7 tens and 2 ones?R
What number has 8 tens and 2 ones?L
What number has 2 tens and 6 ones?A
0/15 letters found
Clue 4
Skip counting
We see muddy boot prints going down the long hallway. Let us count them by twos to trace where they go. This leaves a clue about the thief's hair!
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
90
39
50
80
65
28
140
80
27
12
25
12
130
10
21
A
90
130
80
12
A
90
55
36
27
50
25
40
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, ___, 100, 110A
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, ___, 30, 35N
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, ___, 14, 16W
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, ___, 60, 65S
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, ___, 30, 32Y
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, ___, 39, 42F
Skip-count by 2s. Fill the blank: 2, 4, 6, 8, ___, 12, 14G
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, ___, 60, 70U
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, ___, 90, 100R
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, ___, 140, 150I
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, ___, 45, 50D
Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, ___, 70, 75L
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, ___, 30, 33O
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, ___, 42, 45C
Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, ___, 150, 160B
Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, ___, 24, 27H
0/16 letters found
Clue 5
Missing addends — the last clue
The display case needs eight glass jars but only five are left. How many more do we need to find? This final clue points right to the thief!
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
8 + ___ = 14
5 + ___ = 16
9 + ___ = 13
8 + ___ = 13
2 + ___ = 14
1 + ___ = 10
5 + ___ = 6
5 + ___ = 13
2 + ___ = 9
8 + ___ = 11
3 + ___ = 5
Step 2 — cross out the sentence with each answer
1.The villain wound up the pocket sundial, then unrolled the dusty scroll map.
2.The villain flipped the sand timer, then unrolled the dusty scroll map.
3.The villain looked through the spy glass, then dipped the long feather quill.
4.The villain turned the heavy iron key, then dipped the long feather quill.
5.The villain looked through the spy glass, then unrolled the dusty scroll map.
6.The villain wound up the pocket sundial, then dipped the long feather quill.
7.The villain polished the brass compass, then stamped a red wax seal.
8.The villain polished the brass compass, then shined the gold crown.
9.The villain polished the brass compass, then unrolled the dusty scroll map.
10.The villain polished the brass compass, then dipped the long feather quill.
11.The villain polished the brass compass, then dropped a shiny silver coin.
12.The villain wound up the pocket sundial, then dropped a shiny silver coin.
Solve it
Name the culprit
Choose the one suspect left standing.
Answer Key — The Museum of Yesterday Mystery
Culprit: Susan (brass compass · feather quill · right handed · curly brown wig · train whistle)
- Clue 1 (Subtraction): "THE THIEF DOES NOT HAVE A GOLD CROWN"39 - 8 = 31 (T) · 48 - 15 = 33 (E) · 105 - 31 = 74 (R) · 42 - 16 = 26 (W) · 108 - 30 = 78 (F) · 92 - 38 = 54 (D) · 69 - 23 = 46 (C) · 44 - 5 = 39 (O) · 61 - 4 = 57 (N) · 89 - 24 = 65 (V) · 75 - 23 = 52 (S) · 38 - 17 = 21 (A) · 59 - 14 = 45 (L) · 96 - 35 = 61 (I) · 71 - 29 = 42 (H) · 69 - 13 = 56 (G)
- Clue 2 (Addition): "THE SUSPECT WROTE WITH THEIR RIGHT HAND"41 + 18 = 59 (T) · 9 + 20 = 29 (I) · 44 + 52 = 96 (W) · 25 + 18 = 43 (P) · 43 + 52 = 95 (H) · 29 + 49 = 78 (N) · 33 + 50 = 83 (E) · 24 + 37 = 61 (S) · 9 + 13 = 22 (D) · 26 + 19 = 45 (O) · 20 + 8 = 28 (R) · 40 + 24 = 64 (U) · 28 + 42 = 70 (C) · 22 + 19 = 41 (G) · 29 + 26 = 55 (A)
- Clue 3 (Place value): "THEY WERE SCARED OF THE TRAIN WHISTLE"What number has 5 tens and 9 ones? = 59 (T) · What number has 4 tens and 6 ones? = 46 (C) · What number has 6 tens and 1 one? = 61 (H) · What number has 3 tens and 2 ones? = 32 (F) · What number has 6 tens and 7 ones? = 67 (Y) · What number has 5 tens and 8 ones? = 58 (E) · What number has 1 ten and 4 ones? = 14 (D) · What number has 6 tens and 3 ones? = 63 (S) · What number has 9 tens and 8 ones? = 98 (W) · What number has 3 tens and 8 ones? = 38 (N) · What number has 9 tens and 7 ones? = 97 (O) · What number has 5 tens and 4 ones? = 54 (I) · What number has 7 tens and 2 ones? = 72 (R) · What number has 8 tens and 2 ones? = 82 (L) · What number has 2 tens and 6 ones? = 26 (A)
- Clue 4 (Skip counting): "A CURLY BROWN WIG HAIR WAS FOUND"Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, ___, 100, 110 = 90 (A) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, ___, 30, 35 = 25 (N) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, ___, 14, 16 = 12 (W) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, ___, 60, 65 = 55 (S) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, ___, 30, 32 = 28 (Y) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, ___, 39, 42 = 36 (F) · Skip-count by 2s. Fill the blank: 2, 4, 6, 8, ___, 12, 14 = 10 (G) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, ___, 60, 70 = 50 (U) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, ___, 90, 100 = 80 (R) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, ___, 140, 150 = 130 (I) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, ___, 45, 50 = 40 (D) · Skip-count by 5s. Fill the blank: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, ___, 70, 75 = 65 (L) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, ___, 30, 33 = 27 (O) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, ___, 42, 45 = 39 (C) · Skip-count by 10s. Fill the blank: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, ___, 150, 160 = 140 (B) · Skip-count by 3s. Fill the blank: 3, 6, 9, 12, 15, 18, ___, 24, 27 = 21 (H)
- Clue 5 (Missing addends): surviving statement (box 10) → Susan8 + ___ = 14 = 6 · 5 + ___ = 16 = 11 · 9 + ___ = 13 = 4 · 8 + ___ = 13 = 5 · 2 + ___ = 14 = 12 · 1 + ___ = 10 = 9 · 5 + ___ = 6 = 1 · 5 + ___ = 13 = 8 · 2 + ___ = 9 = 7 · 8 + ___ = 11 = 3 · 3 + ___ = 5 = 2
About this mystery
- Grade level
- Grade 2 math
- Math topics
- Subtraction, Addition, Place value, Skip counting, Missing addends
- Reading level
- grades 1-2
- Theme
- The Museum of Yesterday Mystery — set in The Museum of Yesterday
- Format
- Interactive online & printable worksheet with answer key
- Solution
- One unique, verified culprit among 21 suspects