Rational Numbers – Class 8.

Chapter 1 of NCERT/CBSE Class 8 Maths is about Rational Numbers. Here in this lesson you can find practice problems for this chapter.

MODEL QUESTIONS FOR CBSE CLASS 8 MATHEMATICS
Rational Numbers – Class 8
Fill in the blanks:

1. The rational number which is equal to its additive inverse is ———
2. (-5/7) x ——– = 1.
3. The additive inverse of 5 is ———–
4. ———– is called the identity for the addition of rational numbers.
5. For all rational numbers a, b and c, a (b – c) = ab – ac. This property is known as —————-
6. The multiplicative inverse of (-1) is ————-
7. The reciprocal of a negative rational number is ————-
   Answer the following:
8. Verify that – (-x) is the same as x for x = -11/13.
9. Tell what property allows you to compute ½ x (4 x ¼) as (½ x 4) x ¼.
10. Is 2/7 the multiplicative inverse of 3 ½?
11. Is 0.7 the multiplicative inverse of 1 3/7?
12. Write any three rational numbers between -4 and 0?
13. Write five rational numbers greater than -5?
14. Write five rational numbers less than 0?
15. Write the additive and multiplicative inverse of 2?

ANSWERS:

1. Zero
2. -7/5
3. -5
4. Zero
5. Distributivity of Multiplication over subtraction.
6. -1
7. Negative
8. Given x = -11/13.
   Here we need to prove that – (-x) = x.
   LHS = – (-x) = – (-(-11/13) = -11/13 = x.
   So verified.
9. Associativity of multiplication.
10. Yes.
    3 ½ = (3 x 2 + 1)/2 = 7/2.
    Multiplicative inverse of 7/2 is 2/7.
11. Yes
    1 3/7 = (1 x 7 +3)/7 = 10/7.
    Also 0.7 = 7/10.
12. Three rational numbers between -4 and 0 are -3, -2, -1.
13. Many rational numbers we can write.
    Some of the rational numbers are -4, -3, -2, -1, 0, 1……
14. Many rational numbers we can write.
    Some of the rational numbers are -1, -1/2,-3/2, -2, -3 …..
15. Additive inverse of 2 is (-2) and multiplicative inverse of 2 is ½.