Sort:  

Basically in over simplified terms it is the sum of two previous transactions that can only be arrived at if the numbers add up. 👍

images.png

In cryptography and computer science, a hash tree or Merkle tree is a tree in which every leaf node is labelled with the hash of a data block, and every non-leaf node is labelled with the cryptographic hash of the labels of its child nodes.

Source - Wikipedia

oh, that is in over simplified terms? My gosh I'm hopeless! lol. But thank you sir molometer!