If you put brackets around (2+1), your method of working is: 1) 15-4*(2+1)=3 2) 15-4*3=3 3) 15-12=3 You don't need any more brackets, as the BIDMAS (brackets, Indices, division, multiplication, addition, subtraction) rule does the rest of the job for you. The answer is therefore: 15-4*(2+1)=3
