CBSE Class 8 Mathematics Playing with Numbers Assignment Set B

Question. The number (10n – 1) is divisible by 11 for ___.
(A) n ∈ N
(B) Odd values of n
(C) Even values of n
(D) n is the multiple of 11
Answer : C

Question. Suppose that the division N ÷ 5 leaves a remainder of 4 and the division N ÷ 2 leaves a remainder of 1. What must be the ones digit of N?
(A) 7
(B) 3
(C) 9
(D) 4
Answer : C

Question. Given that the number 148101a095 is divisible by 11, where a is single digit number, what are the possible values of a?
(A) 4
(B) 1
(C) 7
(D) 9
Answer : A

Question. If 1 A B and there is no carry on addition,
         C C A
       + 6 9 7
then the value of B is ____.
(A) 5
(B) 4
(C) 3
(D) 2
Answer : C

Question. The largest natural number by which the product of three consecutive even natural numbers is always divisible, is ____.
(A) 16
(B) 24
(C) 48
(D) 96
Answer : C

Question. If in a number, difference between the sum of digits at its odd places and that of digits at the even places is given 0, then the number is divisible by ____.
(A) 7
(B) 9
(C) 5
(D) 11
Answer : D

Question. If N divided by 5 leaves a remainder of 3, then one’s digit of N must be ____.
(A) Either 3 or 6
(B) Either 3 or 8
(C) Either 8 or 1
(D) Either 8 or 6
Answer : B

Question. Given that the number 67y19 is divisible by 9, where y is a single digit, what is the least possible value of y?
(A) 3
(B) 9
(C) 7
(D) 4
Answer : D

Question. The values of A and B in the given addition respectively are _____.
(A) 4, 7                 2  3  A
(B) 7, 4              + A  3  B
(C) 5, 6                 6  B  1
(D) 6, 5
Answer : A

Question. A 5-digit number xy235 is divisible by 3 such that x + y < 5, where x and y are single digits, then possible values of (x, y) are ____.
(A) (1, 1) or (4, 0)
(B) (1, 1) or (2, 0)
(C) (1, 1) or (0, 2)
(D) (2, 0) or (0, 2)
Answer : B

Question. How many 5-digit numbers of the form AABAA is divisible by 33?
(A) 1
(B) 3
(C) 0
(D) infinite
Answer : B

Question. Find the value of A, B and C respectively

(i)          A   8   3 
          x      C   9
        A   0   4   A
+ 1   5   B   B   0
   C  C   A   0   A

(ii)

              4   3   A   4
                   x   3   A
         B   7   C  7   6
+  B   C   0  C   2   0
    B   4   7   6   9   6

         (i)                     (ii)
(A) 2, 6, 7               9, 5, 2
(B) 6, 7, 2               4, 3, 1
(C) 7, 5, 2               9, 2, 5
(D) 7, 6, 2               4, 1, 3
Answer : D

Question. If A B, , then the value of B is _________.
       × A 3
       5 7 B
(A) 5
(B) 2
(C) 0
(D) 4
Answer : A

Question. Which of the following statements is INCORRECT?
(A) All even natural numbers which are divisible by 3 are also divisible by 6.
(B) If a natural number is divisible by 21, then it is divisible by both 3 and 7.
(C) If AB × 4 = 192, then A + B = 10
(D) A number of the form 14 N + 2 leaves the remainder 2 when divided by 7.
Answer : C

Question. In a division, the divisor is 12 times the quotient and 5 times the remainder. If the remainder is 48, then dividend is ____.
(A) 240
(B) 576
(C) 4800
(D) 4848
Answer : D

Question. The greatest value that must be given to x so that the number 7713 x 8 is divisible by 4 is ___.
(A) 1
(B) 6
(C) 8
(D) 7
Answer : C

Question. If 1 A , where A and B are single digit
        x A
        B 6
numbers, such that B – A = 3, then the values of A and B respectively are ____.
(A) 4, 5
(B) 9, 6
(C) 5, 4
(D) 6, 9
Answer : D

Question. A 3-digit number ‘cba’ is divisible b.y 3 if ____.
(A) a + 2b + c is divisible by 3
(B) 2a + b + c is divisible by 3
(C) a + b + 2c is divisible by 3
(D) a + b + c is divisible by 3
Answer : D

Question. Match the following

(A) (P) → (iii); (Q) → (ii); (R) → (iv); (S) → (i)
(B) (P) → (ii); (Q) → (iv); (R) → (i); (S) → (iii)
(C) (P) → (iii); (Q) → (iv); (R) → (i); (S) → (ii)
(D) (P) → (ii); (Q) → (iii); (R) → (i); (S) → (iv)
Answer : C

Question. Fill in the blanks.
(i) If sum of 3-digit numbers xyz, yzx and zxy is divided by (x + y + z), then quotient is P .
(ii) The difference between 2-digit numbers ab and ba, (where a > b) is divided by 3. The quotient is Q .
(iii) Sum of a 2-digit number and the number obtained by reversing its digits is always divisible by R .
         P               Q               R
(A) 111          3(a + b)         11
(B) 99            (a + b)           7
(C) 111          3(a – b)         11
(D) 99            (a – b)           3
Answer : C