Megiallh 13b Silver and the Tree

It is said in the Megillah (3:11) vayomer hamelech leHaman hakesef nasun lach, then the king said to Haman, “ the silver is given to you.” Tosfos in Megillah 13b writes that the word hakesef, the silver, equals in gematria the word haeitz, the tree, as this was a hint to Haman that he would be hung on the tree. It is noteworthy that Achashveirosh added the word lach, to you, and the word lach is in gematria 50. This alludes to the idea that Haman was hung on a tree that was fifty cubits high.