Numbers

Q. Choose the correct option which shows the prime factorisation of 90.

1. $2\times 9\times 5$

2. $2\times 3\times 3\times 5$

3. $2\times 3\times 15$
4. $6\times 3\times 5$

Q. In a queue of children, Aman is fifth from the left and Sunil is sixth from the right. When they interchange their places among themselves, Aman becomes thirteenth from the left. Then, what will be Sunil’s position from the right?

1. 8th
2. 16th
3. 15th
4. 14th

Q.

The ___ property states that we can add rational numbers in any order.

Q.

Which of the following is an irrational number?

i) $2\sqrt{3}$

ii) $0.143\overline{32}$

iii) $5.\overline{46}$

iv) $\sqrt{5}$

1. ii) and iii)
2. All of the above
3. i) and iv)
4. Only iv)

Q.

Arrange the fractions in descending order

$\frac{2}{6},\frac{5}{3},\frac{3}{4},\frac{2}{7}$

1. $\frac{5}{3},\frac{3}{4},\frac{2}{6},\frac{2}{7}$

2. $\frac{5}{3},\frac{3}{4},\frac{2}{7},\frac{2}{6}$

3. $\frac{5}{3},\frac{2}{6},\frac{3}{4},\frac{2}{7}$

4. $\frac{3}{4},\frac{5}{3},\frac{2}{6},\frac{2}{7}$

Q.

$\frac{5+\sqrt{2}}{5-\sqrt{2}}=m+n\sqrt{2}$

Find the value of m and n

1. $m=3andn=\sqrt{2}$

2. $m=9andn=\frac{10}{3}$

3. $m=27andn=10$

4. $m=\frac{10}{3}andn=9$

Q.

$x^2=11+2\sqrt{30}$, find x

1. zero is a natural number

2. 6.5 is an integer

3. -1 is a whole number

4. All of these

Q. What is the HCF of 18 and 30?

1. 2
2. 6
3. 3
4. 5

Q. The sum of three non-zero prime numbers is 100. One of them exceeds the other by 36. Find the largest number.

1. 73
2. 91
3. 67
4. 57

Q. HCF of 36 and 45 is 9. Their LCM will be:

1. 180
2. 660
3. 160
4. 100