For simplifying an expression, there are some rules about the order in which the calculations should be performed. The order of rules is called BODMAS. BODMAS in mathematics refers to an order of operation. BODMAS refers to the order of dealing with the sums in the brackets first, followed by those linked by the term ‘of’, then division, multiplication, addition and lastly subtraction.

For example: Consider the expression 12 + 7 × 2
In order to simplify this expression 7 is multiplied with 2 and the result is added to 12.
12 + 7 × 2 = 12 + 14 = 26

BODMAS is Bracket Of Division Multiplication Addition Subtraction.
It explains the order of operation in maths. for example
(3+4 ) * 1 will be evaluated as 3+4 = 7 +1 = 8
bracket comes before multiplication
if we have 3+4*1 the answer becomes 4*1 = 4+3 = 7
because multiplication comes before addition