RBSE Class 8 Maths Important Questions Chapter 16 Playing with Numbers

Rajasthan Board RBSE Class 8 Maths Important Questions Chapter 16 Playing with Numbers Important Questions and Answers.

RBSE Class 8 Maths Chapter 16 Important Questions Playing with Numbers

Multiple Choice Questions:

Question 1.
The expanded form of 37 is:
(a) 37 = 3 + 7
(b) 37 = 10 × 3 + 7
(c) 37 = 7 × 10 + 3
(d) 37 = 37 + 3 + 7
Answer:
(b) 37 = 10 × 3 + 7

Question 2.
A two digit number ab can be written as:
(a) 10a + b
(b) a + 10b
(c) 106 + a
(d) a + b
Answer:
(a) 10a + b

Question 3.
ab + ba = 11 (a + b) is divisible by:
(a) 4
(b) 5
(c) 11
(d) ab
Answer:
(c) 11

Question 4.
In ab - ba = 9 (a - b), if a = b, the which of the following is true?
(a) ab = 9
(b) ba = 9
(c) ab - ba = 9
(d) ab - ba = 0
Answer:
(d) ab - ba = 0

Question 5.
Which of the following is divisible by 9?
(a) 11446487
(b) 21436587
(c) 3489
(d) 56789
Answer:
(b) 21436587

Question 6.
In a three digit number 24x is divisible by 9, then the value of x will be:
(a) 3
(b) 4
(c) 5
(d) 6
Answer:
(a) 3

Question 7.
Which of the following is divisible by 2?
(a) 4438
(b) 5791
(c) 233
(d) 147
Answer:
(a) 4438

Fill in the blanks:

Question 1.
If ab is a two digit number, then ab = _________ + b
Answer:
10a

Question 2.
A number is divisible by _________, if it has even digit in it’s ones place.
Answer:
2

Question 3.
If 1 is obtained as the remainder in the division N ÷ 2, then the digit at the ones place of N is _________
Answer:
1, 3, 5, 7 or 9

Question 4.
If a three digit number 24 x is a multiple of 3, then value of x is _________
Answer:
0, 3, 6 or 9

Question 5.
A number is divisible by _________ if it has zero in its ones place.
Answer:
10

Very Short Answer Type Questions:

Question 1.
If a two digit number ab can be written as 10a + b, then write down the value of ba.
Answer:
10b + a.

Question 2.
Write the expanded form of a three digit number abc.
Answer:
100a + 10 b + c.

Question 3.
What is the divisibility test for 5?
Answer:
A number which has either 0 or 5 in it’s unit’s place is divisible by 5.

Question 4.
What is the divisibility test for 9?
Answer:
If the sum of the digits of a number is divisible by 9, then the number itself is divisible by 9.

Question 5.
In 99a - 99 c, if a = c, then what will be the difference?
Answer:
Zero.

Short Answer Type Questions:

Question 1.
If 31Z5 is a multiple of 9 where Z is a digit, then what can be the values of Z?
Answer:
Given that 31Z5 is a multiple of 9 i.e., 31Z5 is divisible by 9
Therefore, 3+1+Z+5 = 9 + Z must be a multiple of 9 i.e., (9 + Z) Should be divisible by 9
Hence, 9 + Z Should be 0, 9, 18, 27,  
⇒ 9 + Z = 9 or 9 + Z= 18
Z = 0 or Z = 9
(∴ 9 + Z can not be equal to zero)
therefore Z = 0, or 9 can be possible.