Selina Concise Class 7 Math Chapter 13 Set Concepts Exercise 13A Solution
EXERCISE 13A
(1) Find whether or not, each of the following collections represent a set:
(i) Not a set
(ii) Set
(iii) Not a set
(iv) Not a set
(v) Set
(2) State whether true or false:
(i) True
(ii) True
(iii) True
(iv) True
(4) Express each of the following sets in roster form:
(i) {17, 19, 21, 23, 25}
(ii) A = {C, H, I, T, A, M, B, R}
(iii) B = {16, 18, 20, 22, 24, 26}
(iv) P = {A, I, E}
(v) S = {0, 1, 4, 9, 16, 25, 36, 49}
(vi) {12, 18, 24, 30, 36, 42, 48, 54, 60, 66, 72, 78, 84, 90}
(vii) C = {4, 6, 8, 9, 10, 12, 14, 15, 16, 18}
(viii) D = {2, 3, 5, 7, 11, 13, 17, 19, 23}
(ix) E = {2, 4, 5, 6, 8, 10, 12, 14, 15, 16, 18, 20, 22, 24, 25, 26, 28}
(x) F = {1, 2, 3, 4, 6, 8, 12, 24}
(xi) G = {triangle, circle, square}
(xii) H = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
(xiii) J = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
(xiv) K = {- 2, – 1, 0, 1, 2, 3, 4}
(5) Express each of the following sets in set-builder notation:
(i) {x : x is a natural number divisible by 3; x < 18}
(ii) {x : x is prime number}
(iii) {x : x is perfect square natural number; x ≤ 36}
(iv) {x : x is a whole number divisible by 2}
(v) {x : x is one of the first three days of the week}
(vi) {x : x is an odd natural number; x ≥ 23}
(vii) {x : x = 1/n, where n is a natural number; 3 ≤ n ≤ 8}
(viii) {x : x is a natural number divisible by 7; 42 ≤ x ≤ 77}
(6) A = {2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24}
B = {1, 4, 9, 16}
C = {3, 6, 9, 12, 15, 18, 21, 24}
D = {2, 3, 5, 7, 11, 13, 17, 19, 23}