Just use PEMDAS
2+3-4 (5x4)
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction So first is Parenthesis 5x4=20 next will be Addition because there are no exponents 2+3= 5-4= 1 so now we go back to multiplication 20 x 1= 20 so 20 is your answer.
Hope I helped out ^^