Bip39 Checksum. The seed phrase can be converted into a range that is utilised given that the seed integer into a deterministic wallet that generates every one of the important pairs used in the wallet. For words that have only three letters, there is no 4th letter. For example With https://thetopdirectory.com/listings13013148/bip39-passphrase-https-linktr-ee-bip39-how-much-you-need-to-expect-you-ll-pay-for-a-good-bip39-words