### I. 'BODMAS'Rule:

This rule depicts the correct sequence in which the operations are to be
executed,so as to find out the value of a given expression.

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Here, 'B' stands for 'bracket' ,'O'for 'of' , 'D' for' division' and 'M' for 'multiplication', 'A'
for 'addition' and 'S' for 'subtraction'.
Thus, in simplifying an expression, first of all the brackets must be removed, strictly in the
order(), {} and [].

After removing the brackets, we must use the following operations strictly in the order:
(1)of (2)division (3) multiplication (4)addition (5)subtraction.

### II. Modulus of a real number :

Modulus of a real number a is defined as
|a| ={a, if a>0
-a, if a<0
Thus, |5|=5 and |-5|=-(-5)=5.

### III. Virnaculum (or bar):

When an expression contains Virnaculum, before applying the
'BODMAS' rule, we simplify the expression under the Virnaculum.