LEARN MATH STEP BY STEP THROUGH VERY EASY PROCESS

ROSTER OR TABULAR METHOD

**Roster method Or Tabular Form **

**In this method, we represent a set by listing all its
elements between braces**

**Example.–1)**** The set X of
the vowels of the English alphabet is represented as X = { a, e, i, o, u }**

**Example.-2)**** the set X of
the days of a week is represented as X = { Monday, Tuesday, Wednesday,
Thursday, Friday, Saturday, Sunday }**

**Example.-3)**** The set X of
the month of a year is represented as X = { January, February,
March, April, May, June, July, August, September, October, November, December }**

**The order in which we list the elements of a set within
braces is immaterial. Thus each of the following denotes the same set,**

** { a, b, c }, { b, a, c }, { a, c, b }, { c, a, b }, {
c, a, b }, { b, c, a }**

**In listing the elements of a set in the tabular form, we do
not repeat any elements. Thus, if ‘Y’ is the set of digits in the number 324,
4512, 1234, 458, 875, 8426 then Y = { 3, 2, 4, 5, 1, 8, 7, 6 }**

**Write each
of the following sets in the Roster Form or Tabular Form**

**1) The set of the months in a year that end with y**** **

**Ans.) If ‘Y’ is the set of month of the year-end
with y then the set is –**

** Y = { January, February, May,
July } (Ans.)**

** **

**2) Find the set of the months in a
year that has 30 days**

**Ans.) If ‘A’ is the set of the months of the year
which has 30 days, then the desired set would be –**

** A = { April, June, September, November } (Ans.)**

** **

**3) Find the set of the odd numbers between 20 to 40,**

**Ans.) If ‘X’ is a set of the odd number between 20
to 40, then**

**
**

** X
= { 21, 23, 25, 27, 29, 31, 33, 35, 37, 39 } (Ans.)**