a=9 b=5 x=a%b it mean x%*b mat result =0.45

Answer 1

No,
% is modulo,
this means that x = 4

Answer 2

5 only fit once in 9 and the rest you have is 4 and that rest you got left is called modulo. if you had number 10 and divided by 5 then 5 fits twice in 10 so there was no modulo or if asked for modulo it'd be 0 as output