Algorithmic Numeral · entry 6 Algorithmic encodings for 6. Adjacent 5 · 7 T9 keypad MNO T9 phone-keypad letter set per digit Leet G leet substitution: 0=O, 1=I, 3=E, 4=A, 5=S, 7=T, etc. Math 2 × 3 prime factorization Previous 5 7 Next