Solution #30: A Story of 1's and 2's
11...1 - 22...2 = 11...1 11...1 - 2(11...1)
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2n times n times n times n times n times
= 11...1 00...0 - 11...1
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n times n times n times
= 11...1 x (100...0 - 1)
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n times n times
= 11...1 x 99...9
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n times n times
= 11...1 x 9 x 11...1
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n times n times
= 32 x 11...12
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n times
= 33...32
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n times
Example: 11 - 2 = 9 = 32.
Source: Berrondom, Marie
Categories: Reasoning, Number sense, Arithmetic, Magic
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