I like this one

GamerExpress

Banned
Aug 28, 2005
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Claire has put some letter blocks together to make the following sum:
ONE + TWELVE = THIRTEEN
Nicola uses all these blocks but rearranges some of them to get a different sum, which is also correct. Then Claire replaces the I with the E and inserts another + block. She rearranges the blocks again and once more the result is correct.
Can you find the two new versions?

This one is my favorite.