2+(5*3) = 17

2+15 = 17

with or without parentheses “order of operations” tells us

multiplication happens before addition.

Perhaps you remember from way back

PEMDAS or

Please Excuse My Dear Aunt Sally

Parentheses

Exponents

Multiplication and Division (left to right)

Addition and Subtraction (left to right)

while putting parentheses around the multiplication portion definitely puts it first on the list of operations, even without them

multiplication is done before addition.

I hope this helps clarify, why your first instinct was correct and

2+5×3=17 is correct, and is done thus,

2+15=17

17=17.

5×3=15+2=17…

REMEMBER THE ORDER OF OPERATIONS!!! PDMAS [paranthesis, division, multiplication, addition, subtraction]..so it will be 5*3 [answer, 15] and then 15 +2 [answer, 17] NOT left to right like when you read..=D hope it helps..