**1.Write the following in decimal form and say what kind of decimal expansion each has :**

**(i) 36/100**

**Solution:**

Hence, the decimal expansion of 36/100 is terminating.

**(ii)1/11**

**Solution:**

Hence, the decimal expansion of 1/11 is non-terminating repeating.

**(iii) 4 ^{1}/_{8}**

**Solution:**

Hence, the decimal expansion of **4 ^{1}/_{8}** is terminating.

**(iv) 3/13**

**Solution:**

Here, the repeating block of digits is 230769

Hence, the decimal expansion of 3/13 is non-terminating repeating.

**(v) 2/11**

**Solution:**

Here, the repeating block of digits is 18.

Hence, the decimal expansion of 2/11 is non-terminating repeating.

**(vi) 329/400**

**Solution:**

Hence, the decimal expansion of 329/400 is terminating.

**2.You know that 1/7 = 0.142857. Can you predict what the decimal expansions of 2/7, 3/7, 4/7, 5/7, 6/7 are, without actually doing the long division? If so, how?**

**[Hint: Study the remainders while finding the value of 1/7 carefully.]**

**Solution:**

**3.Express the following in the form p/q where p and q are integers and q ≠ 0.**

**Solution:**

**(i)**

We can write given question as 0.6666….

Let, x = 0.6666…. equation(i)

Now, multiply both side by 10.

10 x = 6.6666….equation(ii)

Substracting equation (i) from equation(ii), we get

9x = 6

x = 6/9 = 2/3

Hence, required answer is 2/3

**(ii)**

We can write given question as 0.47777….

Let, x = 0.477777…. equation(i)

Now, multiplying both side by 10.

10 x = 4.7777….equation(ii)

Substracting equation (i) from equation(ii), we get

9x = 4.3

x = 43/90

Hence, required answer is 43/90

**(iii)**

We can write given question as 0.001001….

Let, x = 0.001001…. equation(i)

Now, multiply both side by 1000.

1000 x = 1.001001….equation(ii)

Substracting equation (i) from equation(ii), we get

999x = 1

x = 1/999

Hence, required answer is 1/999

**4.Express 0.99999.. in the form p/q . Are you surprised by your answer? With your teacher and classmates discuss why the answer makes sense.**

**Solution:**

Let x = 0.9999….. say equation (a)

Multiplying both sides by 10,

10x = 9.9999…. say equation (b)

Now, equation(b) – equation(a)

x = 1

The difference between 1 and 0.999999 is 0.000001 which is negligible.

Hence, we can conclude that, 0.999 is too much near to 1.

Therefore, 1 as the answer can be justified.

5. What can the maximum number of digits be in the repeating block of digits in the decimal expansion of 1/17 ? Perform the division to check your answer.

Solution:

According to question: In 1/17, the divisor is 17

Therefore, there are 16 digits in the repeating block of the decimal expansion of 1/17.

**6. Look at several examples of rational numbers in the form p/q (q ≠ 0), where p and q are integers with no common factors other than 1 and having terminating decimal representations (expansions). Can you guess what property q must satisfy?**

**Solution:**

Let us look decimal expansion of the following terminating rational numbers:

1/2 = 0. 5, denominator q = 2^{1}

8/125 = 0.064, denominator q = 5^{3}

7/8 = 0. 875, denominator q =2^{3}

4/5 = 0. 8, denominator q = 5^{1}

Hence, we can observe that the terminating decimal may be obtained in the situation where prime factorization of the denominator of the given fractions has only powers of 2 or powers of 5 or powers of both.

**7. Write three numbers whose decimal expansions are non-terminating non-recurring.**

**Solution:**

According to question:

√2 = 1.414213562

√3 = 1.732050807568

√5 = 2.23606797

√26 =5.099019513592

√101 = 10.04987562112

8. Find three different irrational numbers between the rational numbers 5/7 and 9/11.

Solution:

5/7

9/11

Hence, the required three different irrational numbers between 5/7 and 9/11 are:

(i)0.73073007300073000073…

(ii)0.75075007300075000075…

(iii)0.78080078008000…

**9. Classify the following numbers as rational or irrational according to their type:**

**(i)√23**

**Solution:**

√23 = 4.79583152331…

Since the number is non-terminating non-recurring, not perfect square.Hence, it is an irrational number.

**(ii)√225**

**Solution:**

√225 = 15 = 15/1

Since the number can be represented in p/q form, and it perfect square. Hence, it is a rational number.

**(iii) 0.3796**

**Solution:**

Since the number,0.3796, is terminating, and perfect square. Hence it is a rational number.

**(iv) 7.478478**

**Solution:**

The number,7.478478, is non-terminating but recurring. Hence, it is a rational number.

**(v) 1.101001000100001…**

**Solution:**

Since the number,1.101001000100001…, is non-terminating non-repeating (non-recurring). Hence, it is an irrational number.

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