Label: teaching checksum. Not MD5, SHA-256, bcrypt, scrypt, Argon2, or PBKDF2.
Rule: add the UTF-8 byte values, then keep the last two decimal digits.
A password recovery tool would call a named verifier. This card uses the checksum so the arithmetic can be checked on paper.

Worked stored value: 09
hi -> 104+105=209 -> 09
no -> 110+111=221 -> 21
ok -> 111+107=218 -> 18
Predicted match: hi

Activity stored value: 12
The three activity words and their predicted digits are on candidates.txt.