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From the Fun Fact files, here is a Fun Fact at the Easy level:

Proof with Words

Figure 1
Figure 1

2 + 11 - 1 = 12.

Figure 1 demonstrates a "proof with words"!

Presentation Suggestions:
Write the letters for two and eleven side by side, then cross out the letters for one as you say them.

The Math Behind the Fact:
This short fun fact does not really involve any mathematics, but it is rather amusing. After this see also Proofs Without Words.

How to Cite this Page:
Su, Francis E., et al. "Proof with Words." Math Fun Facts. <http://www.math.hmc.edu/funfacts>.

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Keywords:    arithmetic
Subjects:    other
Level:    Easy
Fun Fact suggested by:   Arthur Benjamin
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