Rational Numbers - Worksheets

CBSE Worksheet 01
Class 08 - Mathematics (Rational Numbers)

General Instructions: All questions are compulsory. Q.1 to Q.2 carries one mark each. Q.3 to Q.7 carries two marks each. Q.8 and Q.9 carries three marks each. Q.10 to Q.12 carries four marks each.

  1. Represent 74on the number line.
  2. Write five rational numbers greater than –2.
  3. State True or False
    1. When we multiply a rational number with 1 we get same number.
    2. A rational number is always a whole number.
    3. All the whole numbers are rational numbers.
    4. All the integers are rational numbers.
  4. Fill in the blanks
    1. Zero has ________ reciprocal.
    2. The product of a rational no. and its inverse is ________.
    3. The numbers 5 and -5 are their own ________.
    4. The number _______ is not the reciprocal of any number.
  5. Match the columns
    Column A
    Column B
    i. The multiplicative inverse of 1711
    a. Not defined
    ii. The reciprocal of -1
    b. 1711
    iii. The reciprocal of 0
    c. -1
    iv. Negative of 1711
    d. 1118
  6. Represent 34 on the number line.
  7. Arrange in ascending order
    25,13,34,16
  8. Which is greater?
    1. 913 and 712
    2. 89 and 910
  9. using appropriate properties find : 25×(37)16×32+114×25.
  10. Compare
    1. 125 and -3
    2. 23 and 58
    3. 45 and 710
  11. What should be subtracted from (3423) to get 16?
  12. Find the multiplicative inverse of .
CBSE Worksheet 01
Class 08 - Mathematics (Rational Numbers)
Solution

  1. 74=134
  2. Five rational numbers greater than –2 are :
    32,1,12,0,12
    1. True
    2. False , it is not necessary that every rational number is whole number.
    3. True
    4. True
    1. Zero
    2. One
    3. Reciprocals
    4. Zero
    1. - d
    2. - c
    3. - a
    4. - b
  3. Divide the number line into 4 equal parts starting from 04,14,....... 44 on the right side of number line. Bold mark 34 as asked in the question  and mark it as any alphabet like A.
  4. LCM of 5, 3, 4 and 6 is 60.
    So, (12,20,15,10)60
    Ascending order: 1560,1060,1260,2060
    34,16,25,13.
    1. (9×(1)(13×(1))=(913) and (7×(1))(12×(1))=(712)
      LCM of 13 and 12 is 156
      (108,91)156
      108156<91156
      Hence, 712 is greater
    2. LCM of 9 and 10 is 90.
      (80,81)90
      8190<8090
      Hence, 89 is greater.
  5. 25×(37)16×32+14×25
    =25×(37)16×32+25×114 . . . . [By commutativity]
    =25×(37)+25×11416×32 . . . . [By associativity]
    =25×{(37)+114}16×32 . . . . [ By distributivity ]
    =25×{(6)+114}16×32
    =25×{514}16×32=1714
    =4728=1128
    1. LCM of 5 and 1 is 5
      (12,15)5
      i.e 125>155
      Hence, 125>3    
    2. LCM of 3 and 8 is 24
      (16,15)24
      i.e. 1624<1524
      Hence, 23<58
    3. LCM of 5 and 10 is 10
      (8,7)10
      i.e. 810<710
      Hence, 45<710
  6. Let the number to be subtracted be x
    (3423)x=16
    [(98)12]x=16
    112+16=x
    x=(1+2)12
    x=312
    x=14
  7.  is the symbol used for undefined.
     =10
    Because, any non zero number divided by zero is undefined or infinity.
    To get reciprocal of 10, zero becomes the numerator and 1 becomes the denominator i.e. 01.
    Hence, zero divided by any non-zero number is zero.
    Therefore, the multiplicative inverse of  is 0.