Write the following sets in roster form: {Months of year whose name begin with vowel}

Hint: Here we use the definition of vowels and find the months that begin with a vowel. Form a set having these months as elements.
* There are 5 vowels in list of English letters i.e. A, E, I, O and U.
* Roaster form a set is the form of a set representing all the elements of the set separated by commas.

Complete step-by-step answer:
We know that there are five vowels in the list of English letters.
The five vowels are A, E, I, O and U.
Now we list the names of 12 months in a year.
1) January
2) February
3) March
4) April
5) May
6) June
7) July
8) August
9) September
10) October
11) November
12) December
From the list of months we see months beginning from a vowel are: April, August and October.
We reject all the months that begin with letters other than vowels. Rejected months are January, February, March, May, June, July, September, November and December.
Now we write the set of months beginning with a vowel in Roaster form.
Let the set of months begin with a vowel in Roaster form. Be represented by A
\[ \Rightarrow A = \]{April, August, October}
April, august and october are the only 3 elements in the roaster form.

Note: Students might make the mistake of confusing roaster form with set builder form. A set builder form is the type that gives a description of the type of elements that will exist under the set. But the roaster form directly states the elements of the set. We cannot tell the number of elements in a set from set builder form, whereas we can count the number of elements from roaster form.