# NCERT Solutions for Class 10 Maths Chapter 1 Exercise 1.1

NCERT Solutions for class 10 Maths Chapter 1 Exercise 1.1 Real Numbers in PDF format updated for new academic session 2020-21. UP Board Solutions for Class 10 Maths (Ex. 1.1). Download NCERT Books based on latest CBSE Syllabus 2020-2021. NCERT Solutions 2020-2021 are in Hindi Medium and English Medium or View in Video Format free for CBSE Board, MP Board as well as UP Board NCERT Books. UP Board High School Students are also using NCERT Textbooks for their Board Exams 2020-2021 So, download UP Board Solutions for Class 10 Maths Exercise 1.1 from here in PDF format free. 10th Maths Exercise 1.1

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## NCERT Solutions for class 10 Maths Chapter 1 Exercise 1.1

 Class: 10 Maths (English and Hindi Medium) Chapter 1: Exercise 1.1

### 10 Maths Chapter 1 Exercise 1.1 Solutions

NCERT Solutions for class 10 Maths Chapter 1 Exercise 1.1 of Real numbers in English & Hindi medium to use it online or download in PDF form. All the solutions are updated for new academic session 2020-21. Download Offline Apps for offline use.

• ### Class 10 Maths Exercise 1.1 Solutions

#### Class 10 Maths Exercise 1.1 Question 1, 2 in Video

Class 10 Maths Exercise 1.1 Question 1 in Video
Class 10 Maths Exercise 1.1 Question 2 in Video

#### Class 10 Maths Exercise 1.1 Question 3, 4 in Video

Class 10 Maths Exercise 1.1 Question 3 in Video
Class 10 Maths Exercise 1.1 Question 4 in Video

#### Class 10 Maths Exercise 1.1 Question 5 in Video

Class 10 Maths Exercise 1.1 Question 5 in Video
Class 10 Maths Exercise 1.1 all Questions in Video

#### Important Terms related to Real Numbers

1. Euclid’s division Lemma: For given positive integers ‘a’ and ‘b’ there exist unique whole numbers ‘q’ and ‘r’ satisfying the relation a = bq + r, o ≤ r < b. 2. Euclid’s division algorithm: HCF of any two positive integers a and b with a > b is obtained as follows:
Step 1 : Apply Euclid’s division lemma to a and b to find q and r such that a = bq + r, 0 ≤ r < b. Step 2 : If r = 0 then HCF (a, b) = b ; if r ≥ 0 then again apply Euclid’s lemma to b and r. Repeat the steps till we get r = 0 3. The fundamental Theorem of Arithmetic: Every composite number can be expressed (factorized) as a product of primes and this factorization is unique, apart from the order in which the prime factors occur.

##### Important Questions for Practice on 10th Maths Chapter 1
1. Write the general form of an even integer. [Answer: 2m]
2. Find the largest integer which divides 245 and 1029 leaving remainder 5 in each case. [Answer: 16]
3. Write the form in which every odd integer can be written taking t as variable. [Answer: 2t +1]
4. If the HCF of 408 and 1032 is expressible in the form 1032y – 408×5, then find y. [Answer: 2]
5. What would be the value of n for n²–1 divisible by 8. [Answer: An odd integer]
6. Two tankers contain 650 litres and 1170 litres of petrol respectively. Find the maximum capacity of a tanker which can measure the petrol of either tanker in exact number of times. [Answer: 130 litres]
7. State whether 7 × 11 × 13 + 7 is a composite number or a prime number. [Answer: Composite]
8. A bookseller purchased 117 books out of which 45 books are of mathematics and the remaining 72 books are of Physics. Each book has the same size. Mathematics and Physics books are to be packed in separate bundles and each bundle must contain the same number of books. Find the least number of bundles which can be made for these 117 books. [Answer: 13]
9. Is 5.131131113… a rational number or irrational number? [Answer: Irrational]

##### Show that the square of any positive integer cannot be of the form (5q + 2) or (5q + 3) for any integer q. [CBSE 2020] [Maths Standard]

Let a be any positive integer and b = 5. Using Euclid’s Division Lemma, a = 5q + r for some integer q ≥ 0 where r = 0, 1, 2, 3, 4 because 0 ≤ r < 5. Therefore, a = 5q or 5q + 1 or 5q + 2 or 5q + 3 or 5q + 4 a^2=(5q)^2 or (5q+1)^2 or (5q+2)^2 or (5q+3)^2 or (5q+4)^2 =(5q)^2 or 25q^2+10q+1 or 25q^2+20q+4 or 25q^2+30q+9 or 25q^2+40q+16 =5(5q^2 ) or 5(5q^2+2q)+1 or 5(5q^2+4q)+4 or 5(5q^2+6q+1)+4 or 5(5q^2+8q+3)+1 =5k_1 or 5k_2+1 or 5k_3+4 or 5k_4+4 or 5k_5+1 Where k1, k2, k3, k4 and k5 are some positive integers. Hence, it can be said that the square of any positive integer cannot be of the form (5q + 2) or (5q + 3) for any integer q.

##### Prove that one of every three consecutive positive integers is divisible by 3. [CBSE 2020] [Maths Standard]

Let a, a + 1, a + 2 be any three consecutive positive integers and b = 3. Using Euclid’s Division Lemma, a = 3q + r for some integer q ≥ 0 where r = 0, 1, 2 because 0 ≤ r < 3. Therefore, a = 3q or 3q + 1 or 3q + 2 Here 3q is divisible by 3. For next number a + 1 = 3q + 1 or 3q + 2 or 3q + 3 Here 3q + 3 is divisible by 3. For next number a + 2 = 3q + 2 or 3q + 3 or 3q + 4 ⇒ a + 2 = 3q + 2 or 3q + 3 or 3(q + 1) + 1 Here 3q + 3 is divisible by 3.

##### An army contingent of 612 members is to march behind an army band of 48 members in a parade. The two groups are to march in the same number of columns. What is the maximum number of columns in which they can march? [CBSE 2020] [Maths Basic]

HCF (612, 48) will give the maximum number of columns in which they can march.
We can use Euclid’s algorithm to find the HCF.
612 = 48 × 12 + 36
48 = 36 × 1 + 12
36 = 12 × 3 + 0
The HCF (612, 48) is 12. Therefore, they can march in 12 columns each.

##### What do you understand by Lemma?

A lemma is a proven statement used for proving another statement.       