[UF148] Matchstick Math

←

147 - Paving the Garden

148 - Matchstick Math

149 - Strange Symbols

→

Matchstick Math (Mathematchsticks in the UK version) is a puzzle in Professor Layton and the Unwound Future.

Puzzle

US Version

The math equation below is written in matchsticks! Read as Roman numerals, it means 1 + 11 = 10.

To make this a valid equation, what's the fewest number matches that you need to move?

UK Version

Here's an equation that's been written using matches. Read as Roman numerals, it means: 1 + 11 = 10.

What's the minimum number of matches you need to move to make this equation valid?

Hints

Click a Tab to reveal the Hint.

US Version

Here's a Roman-numeral primer:

I = 1, II = 2, and III = 3.

IIII, however, does not equal four.

IV = 4 and V = 5, so the I in front of the V means one less than five.

VI = 6, VII = 7, and VIII = 8.

IX = 9, X = 10, and XI = 11.

UK Version

Here's a Roman-numeral refresher:

I = 1, II = 2 and III = 3.

IIII, however, does not equal 4.

IV = 4 and V = 5, so the I in front of the V means one less than five.

VI = 6, VII = 7 and VIII = 8.

IX = 9, X = 10 and XI = 11.

US Version

The answer should reveal itself if you understand Hint One and you're willing to look at things from various points of view.

UK Version

The answer should reveal itself if you understand Hint 1 and you're willing to look at things from various points of view.

US Version

As mentioned in Hint Two, it's important to "look at things from various points of view." In other words, don't be afraid to turn this problem on its head...

UK Version

What Hint 2 is basically telling you is to look at things from different directions...

Flip the equation upside down.

US Version

Well, would you look at that! You don't need to move any matches at all. The equation is completely valid as is!

UK Version

Well, would you look at that! You don't need to move any matches at all. The equation is completely valid as it is!

Solution

Incorrect

Too bad!

There's a twist here somewhere...

Correct

You're on fire!

Zero matches is correct.

If you look at the equation upside down, it becomes 10 = 9 + 1 in Roman numerals.

US Version

The phrase "fewest number of matches" might have tricked you into thinking "at least one match," but "fewest" can mean no matches at all!

UK Version

The phrase "minimum number" might have tricked you into thinking "at least one match", but "minimum number" can mean moving no matches at all!

v · d · ePuzzles in Professor Layton and the Unwound Future

Normal	001 002 003 004 005 006 007 008 009 010 011 012 013 014 UK 015 016 017 018 019 020 021 022 023 024 025 026 027 028 029 030 031 032 033 034 035 036 037 038 039 040 041 042 043 044 045 046 047 048 049 050 051 052 053 054 055 056 057 058 059 060 061 062 063 064 065 066 067 068 069 070 071 072 073 074 075 076 077 078 079 080 081 082 083 084 085 086 087 088 089 090 091 092 093 094 095 096 097 098 099 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168

Weekly	See here for weekly puzzles.

Hidden Door	???

Puzzle Index: CV · DB · UF · LS · MM · AL · VS