When an expression involves all things +, - , x, and divided by, brackets and `of’ the operations inside the brackets are to carried out first, followed by 1of’ operation, then multination or division and lastly, addition or subtraction. This whole thing can be summarized as an acronym `BODMAS’ rule, where `B’ stands for bracket, `O’ for of , `D’ for division, `M’ for multiplication, ‘A’ for addition and `S’ for subtraction.
The Rules for is simplifying expression.
1) If an expression contains brackets, the expression within the brackets should be simplified first.
2) If the expression involves `of’, multiplication (or division), addition, subtraction, then ` of ‘should be performed first, followed by multiplication or division. Then proceeding from the left to the right, addition and subtraction are carried out in the order in which the sign of addition and subtraction are given. It should be noted that if the expression contains `of’ and `division’ always do `of’ first and then do division, in order to get the correct answer.
3) If the expression involves all the four operations, then multiplication and division are carried out first in the order in which they are given from left to right. This order also applies to the operations of addition and subtraction, which are carried out later.
Names of the brackets are given.
( ) is circular bracket
{ } is curly bracket
[ ] is square bracket
When a brocket is precede by plus (+) sign, the bracket is removed with out making any change in the expression.
When a bracket is preceded by minus (-) sign, the bracket is removed by changing `+ to –‘and `- to +’ with the bracket.
When there is a bracket with in a bracket. The innermost bracket is to be removed first, followed by the next innermost and so on.
Violation of the above rule leads to the wrong answer.
This can be explained by taking the following simple example.
Rajesh has five notes, each of rupees of fifty and rupees ten. Find the total amount be has.
As per BODMAS rule, 5 x 50 + 5 x 10 = 250 + 50 = 300
But if we do addition before multiplication, the answer as follows; 5 x 55 x 10 = 2750, which is wrong.