Chapter-5 Number Play — Online MCQ Test
MATHS · Grade 8 · CBSE(NCERT)
Practice Chapter-5 Number Play with a free chapter-wise online MCQ test.
This chapter covers: generalized form - divisibility tests - letters for digits - cryptarithms - number puzzles.
AI-generated questions from basic to board-exam level, with instant results and explanations.
Chapter-5 Number Play — Important Questions & Answers
A number is divisible by 2 if its last digit is ______.
- A. odd
- B. even
- C. prime
- D. greater than 5
Answer: B. even
A number is divisible by 2 if and only if its last digit is even (0, 2, 4, 6, 8).
A number is divisible by 2 if and only if its last digit is even (0, 2, 4, 6, 8).
What is the divisibility test for 5?
- A. The sum of digits must be divisible by 5
- B. The last digit must be 0 or 5
- C. The number must be even
- D. All digits must be divisible by 5
Answer: B. The last digit must be 0 or 5
A number is divisible by 5 if its last digit is either 0 or 5.
A number is divisible by 5 if its last digit is either 0 or 5.
If a three-digit number is written as 'abc' in generalized form, its value is ______.
- A. a + b + c
- B. 100a + 10b + c
- C. abc
- D. 100(a + b + c)
Answer: B. 100a + 10b + c
A three-digit number 'abc' has value 100a + 10b + c, where a is in hundreds place, b in tens place, and c in units place.
A three-digit number 'abc' has value 100a + 10b + c, where a is in hundreds place, b in tens place, and c in units place.
If a number 'abc' is divisible by 11, then which condition must be true?
- A. a + b + c is divisible by 11
- B. (a - b + c) is divisible by 11
- C. a + b + c is even
- D. abc must be a three-digit prime
Answer: B. (a - b + c) is divisible by 11
The divisibility test for 11 for a three-digit number 'abc' is: (a - b + c) must be divisible by 11, or more generally, the alternating sum of digits must be divisible by 11.
The divisibility test for 11 for a three-digit number 'abc' is: (a - b + c) must be divisible by 11, or more generally, the alternating sum of digits must be divisible by 11.
If PQ + QR + RP = PQR, where P, Q, R are distinct digits, then what is the value of P?
- A. 1
- B. 2
- C. 3
- D. 4
Answer: A. 1
PQ + QR + RP = (10P+Q) + (10Q+R) + (10R+P) = 11P + 11Q + 11R = 11(P+Q+R). For this to equal PQR = 100P + 10Q + R, we need 11(P+Q+R) = 100P + 10Q + R. Simplifying: 11P + 11Q + 11R = 100P + 10Q + R gives Q + 10R = 89P, which works when P=1.
PQ + QR + RP = (10P+Q) + (10Q+R) + (10R+P) = 11P + 11Q + 11R = 11(P+Q+R). For this to equal PQR = 100P + 10Q + R, we need 11(P+Q+R) = 100P + 10Q + R. Simplifying: 11P + 11Q + 11R = 100P + 10Q + R gives Q + 10R = 89P, which works when P=1.