On the 30th of November we learnt about hexadecimal, it is a base 16 number, 16 symbols to represent number 0-9 And A-F Corvert 163 into hexadecimal, write in binary, 10100011 the split into 2 4 bit nibbles

8421 8421

1010 0011

this creates A3

8+2 = 10 and 10 in the number is A

2+1 =3