Page 109 - ICSE Math 6

4. Write the following sets in roster form and find their cardinality.
(a) A = {x | –5 ≤ x ≤ 5}

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(b) X = {x | x = y , y = 1, 2, 3, 4}
(c) B = {x | x is a consonant in the word EXAMPLE}
(d) D = {x | x is a 1-digit prime number}

(e) S = {x | x is an odd natural number less than 15}
5. Write the following sets in the roster form.
(a) A = {x | x is a multiple of 5}
(b) B = {x | x is a factor of 60}

(c) X = {x | –4 ≤ x ≤ 2}
(d) Y = {x | x is an odd prime number}
(e) P = {x | x is a letter of the word BEAUTIFUL}
(f) Q = {x | x is a letter of the word SWEET}

6. A teacher needs to divide a class into groups to give each group a project to work on. Which of
the following method can the teacher select to divide the class? Explain.
(a) Dividing class on the basis of students’ roll number.
(b) Dividing class on the basis of students’ intelligence.
(c) Dividng class on the basis of first letter of students’ names.

7. As per the list a zoo inspector made, out of the 15 Asian elephants in the zoo 10 are female. Also,
out of the remaining 20 elephants 13 are female. Find:
(a) The cardinality of set of all the elephants in the zoo.
(b) The cardinality of set of all Asian male elephants in the zoo.

THINK SMART

1. Is the set containing all the elements of two different finite sets finite? Explain.

2. What is the cardinality of the set of all whole numbers that are not natural numbers.
3. Consider the following sets.

A = {January, March, May, July, August, October, December}
B = {x : x is a month with 30 days}
If Nisha’s birthday month does not belong to any of these two sets, find her birthday month.

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