1. 'BODMAS' Rule:

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

    Here B - Bracket,
    O - of,
    D - Division,
    M - Multiplication,
    A - Addition and
    S - 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:

    (i) of (ii) Division (iii) Multiplication (iv) Addition (v) Subtraction.

  2. 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.

  3. Virnaculum (or Bar):

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