a) Perform the multiplication and division first, then the addition.
7 + 3·5 -4÷2 +3
= 7 +15 -2 +3
= 23
__
b) Evaluate parentheses first, then the rest of it. The multiplication and division are done before the addition at the same level.
((7 +3)·5 -4)÷2 +3
= (10·5 -4)÷2 +3
= (50 -4)÷2 +3
= 46÷2 +3
= 23 +3
= 26
_____
<em>Additional comment</em>
An appropriate calculator can evaluate these for you. The Go.ogle calculator reliably follows the order of operations. You can use an asterisk (*) for multiplication with that calculator.