DEMO
Look around freely · sample student, nothing is saved
Get the app
01
12
3
NCERT Solutions · Maths Ch 1
Real Numbers
20 questions · 2 exercises
Closed
Open all
Ex 1.1
Ex 1.2
NCERT answers with full exam-style working, step by step. Tap a question to open its solution.
1
15 QUESTIONS
Exercise 1.1
Q1(i)
Express each number as a product of its prime factors: 140
(1 mark)
Q1(ii)
Express each number as a product of its prime factors: 156
(1 mark)
Q1(iii)
Express each number as a product of its prime factors: 3825
(1 mark)
Q1(iv)
Express each number as a product of its prime factors: 5005
(1 mark)
Q1(v)
Express each number as a product of its prime factors: 7429
(1 mark)
Q2(i)
Find the LCM and HCF of the following pair of integers and verify that LCM × HCF = product of the two numbers: 26 and 91
(2 marks)
Q2(ii)
Find the LCM and HCF of the following pair of integers and verify that LCM × HCF = product of the two numbers: 510 and 92
(2 marks)
Q2(iii)
Find the LCM and HCF of the following pair of integers and verify that LCM × HCF = product of the two numbers: 336 and 54
(2 marks)
Q3(i)
Find the LCM and HCF of the following integers by applying the prime factorisation method: 12, 15 and 21
(2 marks)
Q3(ii)
Find the LCM and HCF of the following integers by applying the prime factorisation method: 17, 23 and 29
(2 marks)
Q3(iii)
Find the LCM and HCF of the following integers by applying the prime factorisation method: 8, 9 and 25
(2 marks)
Q4
Given that HCF (306, 657) = 9, find LCM (306, 657).
(2 marks)
Q5
Check whether 6ⁿ can end with the digit 0 for any natural number n.
(2 marks)
Q6
Explain why 7 × 11 × 13 + 13 and 7 × 6 × 5 × 4 × 3 × 2 × 1 + 5 are composite numbers.
(2 marks)
Q7
There is a circular path around a sports field. Sonia takes 18 minutes to drive one round of the field, while Ravi takes 12 minutes for the same. Suppose they both start at the same point and at the same time, and go in the same direction. After how many minutes will they meet again at the starting point?
(3 marks)
2
5 QUESTIONS
Exercise 1.2
Q1
Prove that √5 is irrational.
(3 marks)
Q2
Prove that 3 + 2√5 is irrational.
(3 marks)
Q3(i)
Prove that the following is irrational: 1/√2
(2 marks)
Q3(ii)
Prove that the following is irrational: 7√5
(2 marks)
Q3(iii)
Prove that the following is irrational: 6 + √2
(2 marks)