Draw DFA (Deterministic finite automaton) of words ending in:

1) Words over {a,b} with odd number of a's or odd number of b's

2) Words over {a,b} ending in babab

3) Words over {a,b} ending in abx, where x is either a or b

4) Words over {a,b} without bbb

5) Words over {a,b,c} with at most one occurrence of abc

6) Words over {0,1} multiple of 2 in binary

The solutions can be checked in https://racso.lsi.upc.edu/juezwsgi/