Write the following sets in roster form

Write the following sets in roster form:

(i) A = {x: x is an integer and -3 < x < 7}.
(ii) B = {x: x is a natural number less than 6}.
(iii) C = {x: x is a two-digit natural number such that the sum of its digits is 8} 
(iv) D = {x: x is a prime number which is divisor of 60}.
(v) E = The set of all letters in the word TRIGONOMETRY. 
(vi) F = The set of all letters in the word BETTER.
Answer
(i) A = {x: x is an integer and -3 < x < 7}
Integer values between -3 and 7 are -2, -1, 0, 1, 2, 3, 4, 5, and 6.
Therefore, set in roster form will be written as A = {-2, -1, 0, 1, 2, 3, 4, 5, 6}

(ii) B = {x: x is a natural number less than 6}
Natural numbers less than 6 are 1, 2, 3, 4, and 5 .
Therefore, set in roster form will be written as B = {1, 2, 3, 4, 5}

(iii) C = {x: x is a two-digit natural number such that the sum of its digits is 8}
Two-digit natural number which sum of its digits is 18, are 17, 26, 35, 44, 53, 62, 71, and 80.
Therefore, set in roster form will be written as C = {17, 26, 35, 44, 53, 62, 71, 80}

(iv) D = {x: x is a prime number which is a divisor of 60}
Number 60 can be divided by 1,2,3,5,6,10,12,15,20,30 and 60 in which 2 ,3 and 5 are prime numbers .
Therefore, set in roster form will be written as D = {2, 3, 5}.

(v) E = The set of all letters in the word TRIGONOMETRY
In roster form we do not repeat any element. Word TRIGONOMETRY has alphabet T, R, I, G, O, N, M, E, and Y
Therefore set in roster form will be written as E = {T, R, I, G, O, N, M, E, Y}

(vi) F = the set of all letters in the word BETTER
In roster form we do not repeat any element. Word BETTER has alphabet B, E, T and R
Therefore set in roster form will be written as F = {B, E, T, R}