All questions of Number Play for Class 6 Exam

The number 14641 is a 5-digit palindrome where the third digit (6) is twice the second digit (3), and the fourth digit (4) is twice the third digit (6).

According to the Collatz Conjecture, if a number is even, it is divided by 2. The next number after 6 (which is even) is 6 ÷ 2 = 3.

The digit '7' appears in the 7th, 17th, 27th, 37th, 47th, 57th, 67th, 70-79 (10 times), and 87th, 97th, totaling 20 times.

The number 38,800 can be formed by adding 25,000, 13,000, and 800 (which is two times 400). The missing number in the equation is 800.

The total number of 2-digit numbers between 10 and 99 is calculated as 99 - 10 + 1 = 90.

To form the largest number, arrange the digits in descending order. The largest number formed by 6382 is 8632.

Number of Digits in a 5-Digit Number

Explanation:
A 5-digit number is a number that has 5 digits in total. Let's break down the explanation further:

• Definition of a Digit: A digit is a symbol used to represent numbers from 0 to 9.
• Understanding Digits in Numbers: In a multi-digit number, each place value position represents a power of 10. The rightmost digit is in the ones place, the next digit to the left is in the tens place, and so on.
• Counting the Digits: To determine the number of digits in a 5-digit number, we simply count the total number of individual digits in the number. Since a 5-digit number has 5 places, it will have a total of 5 digits.

Therefore, the correct answer to the question "How many digits are there in a 5-digit number?" is option B) 5. A 5-digit number consists of 5 individual digits, each representing a specific place value within the number.

The sequence starting from 21 follows 21 → 64 → 32 → 16. The fourth number in the sequence is 16.

On a 12-hour clock, 13:13 does not exist as the hour goes only up to 12. The other times (4:44, 10:10, 12:12) are valid patterns on a 12-hour clock.

The sum of the digits of 176 is 1 + 7 + 6 = 14.

Understanding the Reverse of a Number
To find the reverse of a number, we need to rearrange its digits in the opposite order.
Step-by-Step Process
- Identify the Digits: The number we are working with is 1234. It consists of four digits: 1, 2, 3, and 4.
- Reverse the Order: We take the last digit and move it to the front, followed by the other digits in reverse order.
- Start with the last digit: 4
- Next, take the third digit: 3
- Then the second digit: 2
- Finally, the first digit: 1
- Combine the Reversed Digits: Placing these digits together gives us 4321.
Conclusion
Thus, the reverse of the number 1234 is 4321, which is option 'A'.
Options Breakdown
- a) 4321 - This is the correct answer.
- b) 3412 - Incorrect, as the digits are not in reverse order.
- c) 2143 - Incorrect, as the digits are also not in reverse order.
- d) 3241 - Incorrect for the same reason.
By following these steps, we see that reversing the digits of the number 1234 successfully yields 4321, confirming that option 'A' is indeed the correct answer.

The possible 3-digit palindromes using the digits 1, 2, and 3 are 121, 131, 212, 232, 313, and 323. There are 6 such numbers.

The smallest 4-digit number is 1000, but when reversed, it remains the same. 1001, when reversed, becomes 1001, which is the same, but 1001 is smaller than other options when comparing original and reversed numbers.

A palindromic number reads the same forward and backward. Among the given options, only 12321 is palindromic.

The Kaprekar constant for 4-digit numbers is 6174. No matter what 4-digit number you start with, if you repeat the steps of arranging digits in descending and ascending order, subtracting the smaller from the larger, you will eventually reach 6174.