Brain Teasers
Roman Matches II
The following equation involving Roman numerals is formed using matchsticks. The given equation is wrong. Can you correct it by moving just one matchstick? See if you can do it twice: the equation can be corrected in two different ways. Each solution must be an equation (i.e., it must contain one equals sign).
Note:
I(1) and -(minus) are each formed from one matchstick.
V(5), X(10), L(50), +(plus), and =(equals) are each two matchsticks.
C(100) is three matchsticks.
The incorrect equation is: XI = IX - III
Note:
I(1) and -(minus) are each formed from one matchstick.
V(5), X(10), L(50), +(plus), and =(equals) are each two matchsticks.
C(100) is three matchsticks.
The incorrect equation is: XI = IX - III
Hint
One solution only affects the left side of the equation; the other solution only affects the right side.Answer
First solution: XI = IX + IITake one matchstick from the III and place it across the minus sign (changing it to a plus sign).
Second solution: VI = IX - III
Change the first X into a V by sliding the matchstick in the X that looks like a backslash (\) slightly to the left until the bottom touches the matchstick that looks like a forward slash (/).
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