Hi! When you see problems like this, always refer to PEMDAS!
P - Parenthesis
E - Exponents
M - Multiplication
D - Division
A - Addition
S - Subtraction
Also note that you go from left to right and parenthesis is always first!
18(2-1)÷3+4
Start with the parenthesis and subtract 2 from 1. That'll leave you with 1.
18(1)÷3+4
Next is multiplication since there are no exponents. Multiply 18 by 1. That'll leave you with 18.
18÷3+4
Now, divide 18 from 3. That'll leave you with 6.
6+4
Finally, you may add the final two. 6 plus 4 is 10.
With that being said, the correct answer is 10.