The order of operation has 3 basic "priorities" : B DM AS
"B" means Brackets have the highest priority. Whatever is within the brackets have to be catered first. Be warned that "B DM AS" rule can be nested, which means the deepest layer of brackets have to be operated on before the external brackets.
"DM" means Divide and Multiply have the same priorities. They are solved from left to right according to whether D or M come first.
"AS" means Add and Subtract have the last priorities. They are solved from left to right according to whether A or S come first.
