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Rational Numbers Important Questions

8th Standard EM

Reg.No. :
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Maths

Time : 01:00:00 Hrs
Total Marks : 50
5 x 1 = 5
1. The number which is subtracted from $\frac { -6 }{ 11 }$ to get $\frac { 8 }{ 9 }$

(a)

$\frac { 34 }{ 99 }$

(b)

$\frac { -142 }{ 99 }$

(c)

$\frac { 142 }{ 99 }$

(d)

$\frac { -34 }{ 99 }$

2. Which of the following rational numbers is the greatest?

(a)

$\frac { -17 }{ 24 }$

(b)

$\frac { -13 }{ 16 }$

(c)

$\frac { 7 }{ -8 }$

(d)

$\frac { -31 }{ 32 }$

3. Which of the following pairs is equivalent?

(a)

$\frac { -20 }{ 12 } ,\frac { 5 }{ 3 }$

(b)

$\frac { 16 }{ -30 } ,\frac { -8 }{ 15 }$

(c)

$\frac { -18 }{ 36 } ,\frac { -20 }{ 44 }$

(d)

$\frac { 7 }{ -5 } ,\frac { -5 }{ 7 }$

4. Closure property is not true for division of rational numbers because of the number

(a)

0

(b)

-1

(c)

0

(d)

$\frac { 1 }{ 2 }$

5. $\frac { 1 }{ 2 } -\left( \frac { 3 }{ 4 } -\frac { 5 }{ 6 } \right) \neq \left( \frac { 1 }{ 2 } -\frac { 3 }{ 4 } \right) -\frac { 5 }{ 6 }$ illustrates that subtraction does not satisfy the ________ property for rational numbers.

(a)

commutative

(b)

closure

(c)

distributive

(d)

associative

6. 5 x 1 = 5
7. The value of $\frac { -5 }{ 12 } +\frac { 7 }{ 15 }$ = ________________

()

$\frac { 1 }{ 20 }$

8. The value of $\left( \frac { -15 }{ 23 } \right) \div \left( \frac { +30 }{ -46 } \right)$ is _____________

()

1

9. The multiplicative inverse of $2\frac { 3 }{ 5 }$ is _____________

()

$\frac { 5 }{ 13 }$

10. If -3 x $\frac { -6 }{ 11 }$ = $\frac { -6 }{ 11 } \times x$ is _______________

()

-3

11. If distributive property is true for $\left( \frac { 3 }{ 5 } \times \frac { -4 }{ 9 } \right) +\left( x\times \frac { 15 }{ 17 } \right) =\frac { 3 }{ 5 } \times (y+z)$ then x, y, z are ________ , ________ and ________.

()

$\frac { 3 }{ 5 }$$\frac { -4 }{ 9 }$ and $\frac { 15 }{ 17 }$

12. 5 x 1 = 5
13. 0 is the smallest rational number

(a) True
(b) False
14. There are an unlimited rationals between 0 and 1

(a) True
(b) False
15. The rational number that does not have a reciprocal is 0.

(a) True
(b) False
16. The only rational number which is its own reciprocal is –1.

(a) True
(b) False
17. The rational numbers that are equal to their additive inverses are 0 and –1.

(a) True
(b) False
18. 5 x 1 = 5
19. $\left( \frac { 5 }{ 6 } +-1 \right) +\frac { -3 }{ 4 } =\frac { 5 }{ 6 } +\left( -1+\frac { -3 }{ 4 } \right)$

20. (1)

a rational number

21. $\frac { -1 }{ 3 } \left( \frac { 1 }{ 4 } +\frac { 2 }{ 3 } \right) =\left( \frac { -1 }{ 3 } \times \frac { 1 }{ 4 } \right) +\left( \frac { -1 }{ 3 } \times \frac { 2 }{ 3 } \right)$

22. (2)

multiplicative inverse property

23. $\frac { -4 }{ 9 } \times \frac { 9 }{ -4 } =\frac { 9 }{ -4 } \times \frac { -4 }{ 9 } =1$

24. (3)

distributive property of multiplication over addition

25. $\frac { 1 }{ 0 }$

26. (4)

does not exist

27. $\frac { 22 }{ 7 }$

28. (5)

6 x 2 = 12
29. List five rational numbers between
0.25 and 0.35

30. List five rational numbers between
–1.2 and -2.3

31. Write four rational numbers equivalent to
$\frac { -3 }{ 5 }$

32. Write four rational numbers equivalent to
$\frac { -7 }{ 6 }$

33. Write four rational numbers equivalent to
$\frac { 8 }{ 9 }$

34. If p+2q = 18 and pq = 40, find $\frac { 2 }{ p } +\frac { 1 }{ q }$

35. 6 x 3 = 18
36. Write the following decimal numbers as rationals.
3.0

37. Write the following decimal numbers as rationals.
0.25

38. Write the following decimal numbers as rationals.
0.666…

39. Write the following decimal numbers as rationals.
−5.8

40. Write the following decimal numbers as rationals.
1.15

41. Reduce to the standard form
$\frac { 48 }{ -84 }$