MCQ on Number Play Class 6
Class 6 Maths Chapter 3 MCQ Number Play
Question 1.
What is the largest number that can be formed using the digits 6382?
(a) 8632
(b) 8362
(c) 8623
(d) 8236
Answer:
(a) 8632
Explanation:
To form the largest number, arrange the digits in descending order. The largest number formed by 6382 is 8632.
Hence correct answer is option (a).
Question 2.
How many times does the digit ‘7’ appear when writing all the numbers from 1 to 100?
(a) 10
(b) 15
(c) 20
(d) 25
Answer:
(c) 20
Explanation:
The digit ‘7’ appears in the 7th, 17th, 27th, 37th, 47th, 57th, 67th, 70-79 (10 times), and 87th, 97th, totaling 20 times.
Hence correct answer is option (c).
Question 3.
What is the smallest’4-digit number?
(a) 1000
(b) 1001
(c) 1100
(d) 1010
Answer:
(a) 1000
Explanation:
The smallest 4-digit number is 1000. Hence correct answer is option (a).
Question 4.
The largest 4-digit number, using any one digit twice, from digits 5, 9, 2 and 6 is
(a) 9652
(b) 9562
(c) 9659
(d) 9965
Answer:
(d) 9965
Explanation:
Using 9 as twice from 5, 9, 2 and 6, then the number is 9965.
Hence correct answer is option (d).
Question 5.
The largest 5-digit number having only three different digits is
(a) 98978
(b) 99897
(c) 99987
(d) 98799
Answer:
(c) 99987
Explanation:
In the given options there are three numbers used 9, 8 and 7. To get the largest of 5-digit we have to arrange the numbers in descending order. Then, from the given options 99987 is the largest of 5-digit number. Hence correct answer is option (c).
Question 6.
The total number of 4-digit numbers is
(a) 8999
(b) 9000
(c) 8000
(d) 9999
Answer:
(b) 9000
Explanation:
We know that the smallest four-digit number = 1,000. Largest four-digit number = 9,999. So the total number of four-digit numbers = [9,999 – 1,000] + 1 = 9,000.
Hence correct answer is option (b).
Question 7.
What is the Kaprekar constant for 4-digit numbers?
(a) 495
(b) 6174
(c) 8127
(d) 8372
Answer:
(b) 6174
Explanation:
The Kaprekar constant for 4-digit numbers is 6174.
Hence correct answer is option (b).
Question 8.
Which of the following is the correct sum of digits for the number 176?
(a) 12
(b) 14
(c) 16
(d) 17
Answer:
(b) 14
Explanation:
The sum of the digits of 176 is 1 + 7 + 6 = 14.
Hence correct answer is option (b).
Question 9.
By using dot (.) patterns, which of the following numbers can be arranged in all the three ways namely a line, a triangle and a rectangle? (NCERT Exemplar)
(a) 9
(b) 10
(c) 11
(d) 12
Answer:
(b) 10
Explanation:
Hence correct answer is option (b)
Question 10.
Which of the following numbers is a supercell in the grid [45, 78, 92, 31, 60]?
(a) 45
(b) 78
(c) 92
(d) 60
Answer:
(c) 92
Explanation:
A supercell is a number in a grid that is larger than all of its neighboring numbers. In the given grid, 92 is greater than 78 (to its left) and 31 (to its right), making it a supercell.
Hence correct answer is option (c).
Question 11.
What is the correct order of placing the numbers 2180, 9950, 3050 on a number line?
(a) 2180, 3050, 9950
(b) 3050, 2180, 9950
(c) 9950, 3050, 2180
(d) 2180, 9950, 3050
Answer:
(a) 2180, 3050, 9950
Explanation:
The numbers 2180, 9950 and 3050 should be placed in ascending order on the number line as 2180, 3050, and 9950.
Hence correct answer is option (a).
Question 12.
Fill in the blanks:
(i) Smallest 4-digit number formed by the digits 3, 0, 4,1 is ____
Answer:
1034
(ii) Greatest 4-digit number formed by the digits 0, 8,1, 9 is ____
Answer:
9810
(iii) I am the greatest number made from digit 7,1, 8, 3.
Answer:
8731
(iv) I am the smallest number made from digit 3, 9, 0, 1. ____
Answer:
1039
(v) Smallest 4-digit even number is ____
Answer:
1000
(vi) Largest 4-digit even number is ____
Answer:
9998
Question 13.
State True/False:
(i) The largest s if-digit telephone number that can be formed by using digits 5, 3, .4, 7, 0, 8 only once is 875403.
Answer: False.
The largest six-digit telephone number that can be formed by using digits 5,3,4,7,0,8 only once is 875430.
(ii) The largest 4-digit number formed by the digits 6, 7, 0, 9 using each digit only once is 9760.
Answer:
True.
(iii) The numbers 4578, 4587, 5478, 5487 are in descending order.
Answer: False.
In the question, the arrangement of the numbers in ascending order. Descending order of the given number = 5487, 5478, 4587,4578.
(iv) 8439 is an odd number.
Answer:
True
(v) 2787 is an even number.
Answer:
False
Question 14.
Given the single line grid below, identify which cells are supercells.
253 421 356 789 345 678 234
Solution:
421 is a supercell because it is larger than 253 and 356.
789 is a supercell because it is larger than 356 and 345.
678 is a supercell because it is larger than 345 and 234.
Question 15.
Identify the numbers marked on the number lines below, and label the missing numbers. Put a circle around the smallest number and a box around the largest number in each of the sequences below.
Answer:
Answer:
Question 16.
Can you use Kaprekar’s process with numbers that are not 4-digit numbers, such as 3-digit numbers? Why or why not?
Answer:
Yes, the Kaprekar process specifically works with 4-digit numbers and 3 digit numbers only. If you use a 5-digit or above number, the steps and the constant will not be the same. The process is designed to reach 6174 with 4-digit numbers and 495 with 3 digit numbers.
Question 17.
What if you start with the number 2222? What do you notice?
Answer:
If you start with 2222, all the digits are the same. Subtracting the number from itself gives 2222 – 2222 = 0. Since Kaprekar’s process requires distinct digits, it cannot reach 6174 from this number.
Question 18.
On a 12-hour digital clock, what is the smallest interval between two times that are palindromic (can be read forwards and backwards as the same number)?
Answer:
The interval is two minutes, between the times of 9:59 and 10:01.
Question 19.
Provide a list of all palindromic times in a 12-hour cycle.
Answer:
- 01:10
- 02:20
- 03:30
- 04:40
- 05:50
- 10:01
- 11:11
- 12:21
Question 20.
What are some palindromic dates that occurred in the 21st century?
Answer:
02/02/2020, 12/02/2021, 22/02/2022
Question 21.
Solve 87 + 46 mentally.
Answer:
Break it down in mind 87 + 40 = 127.
Then add 6: 127 + 6 = 133
Question 22.
Solve 76 – 34 mentally.
Answer:
Subtract 30 from 76 in mind 76 – 30 = 46.
Subtract the remaining 4: 46 – 4 = 42
Question 23.
Fill in the missing numbers in the track by understanding the number pattern.
Answer:
7, 14, 21, 28, 35, 42, 49, 56, 63
Question 24.
Start with the number 12. Follow the Collatz rules to find out how many steps it takes to reach 1.
Solution:
Steps to Solve:
- 12 is even, so divide by 2 → 6
- 6 is even, so divide by 2 → 3
- 3 is odd, so multiply by 3 and add 1 → 10
- 10 is even, so divide by 2 → 5
- 5 is odd, so multiply by 3 and add 1 → 16
- 16 is even, so divide by 2 → 8
- 8 is even, so divide by 2 → 4
- 4 is even, so divide by 2 → 2
- 2 is even, so divide by 2 → 1
It takes 9 steps to reach 1.
Question 25.
Name the smallest 4-digit numbers with different digits.
Answer:
The smallest 4-digit number with different digits is 1023.
This number satisfies the given conditions of having four digits and each digit being unique.
Question 26.
Form the largest and smallest 4-digit numbers using each of digits 7, 1, 0, 5 only once.
Solution:
The largest 4-digit number = 7510.
Smallest 4-digit number = 1057.
Therefore, the largest and smallest 4-digit numbers using each of digits 7, 1, 0, 5 only once is 7510 and 1057.
Question 27.
What is the largest 5-digit number with unique digits?
Answer:
98765 is the largest 5-digit number with unique digits.
Question 28.
What happens if you pick any 4-digit number (where not all digits are the same), rearrange the digits to make the largest and smallest numbers possible, subtract the smaller number from the larger one, and repeat the*process? What number do you always end up with?
Answer:
You will always end up with 6174 which is Kaprekar constant.
Question 29.
Why is it important that not all the digits of the 4-digit number are the same while calculating Kaprekar constant?
Answer:
If all the digits are the same (like 1111 or 2222), subtracting the number from itself will always give you 0, and you can’t reach 6174.
Question 30.
Create a grid using numbers from 1 to 7 so that no cell is a supercell.
Answer:
In this arrangement, no cell is larger than its immediate neighbors: 1 2 3 4 5 6 7.
Question 31.
What is the difference between the greatest and the smallest 4-digit number that can be formed using the digits 8, 0, 7, 9?
Solution:
Greatest number = 9870
Smallest number = 7809
Difference = 9870 – 7809
= 2061
Question 32.
Identify the numbers marked on the number lines below, and label the missing numbers. Put a circle around the smallest number and a box around the largest number in each of the sequences below.
Answer:
Answer:
Question 33.
What is the smallest 2-digit number whose digit sum is 9?
Answer:
18
Question 34.
Is the number 45654 a palindrome? Explain why or why not.
Answer:
45654 is a palindrome because it reads the same backward and forward.
Question 35.
Calculate the digit sums for the numbers in the series 12, 23, 34, 45, 56. Look for any patterns in the results.
Answer:
- 12:1 +2 = 3
- 23:2 + 3 = 5
- 34:3 + 4 = 7
- 45:4 + 5 = 9
- 56: 5 + 6= 11
Series shows increasing odd numbers.
