Can I write "return(a*b)" istead of just "return a*b". It's so confusing now not to have parentheses.. Will it make difference?

Answer 1

Theres no difference between them in your example, parenthesis are used to order the way you want your code to operate.

here we have 2 sums which are the same they both follow precedence but in last one I control the order using parenthesis which has a higher precedence over multiplication operator.

(2*2+4*2) //output 12

2*2 = 4;
4*2 = 8;
4+8 = 12;

(2*(2+4)*2) //output 24

2+4 = 6:
2*6 = 12;
12*2 = 24;

Answer 2

Yes you can but make sure that there is a space after the return statement