FAQs on Maths- How to test divisibility by 8,11- English

Question 1

1. How can I check if a number is divisible by 8?

Accepted Answer

Ans.To determine if a number is divisible by 8, you only need to look at the last three digits of the number. If those last three digits form a number that is divisible by 8, then the entire number is divisible by 8. For example, to check if 5,432 is divisible by 8, look at 432. Since 432 ÷ 8 = 54, which is a whole number, 5,432 is divisible by 8.

Question 2

2. What is the rule for testing divisibility by 11?

Accepted Answer

Ans.To test if a number is divisible by 11, subtract the sum of the digits in the odd positions from the sum of the digits in the even positions. If the result is 0 or divisible by 11, then the number is divisible by 11. For instance, for the number 2728, the sum of the odd-position digits (2 + 2) is 4, and the sum of the even-position digits (7 + 8) is 15. The difference is 15 - 4 = 11, which is divisible by 11, so 2728 is divisible by 11.

Question 3

3. Can you provide an example of a number that is divisible by 8?

Accepted Answer

Ans.An example of a number that is divisible by 8 is 1,024. To check, look at the last three digits, which are 024. Since 24 ÷ 8 = 3, which is a whole number, 1,024 is divisible by 8.

Question 4

4. Is there a quick way to check if larger numbers are divisible by 11?

Accepted Answer

Ans.Yes, for larger numbers, you can still apply the rule for 11 by breaking the number down into groups of digits. For example, for 987,654,321, you can group the digits: (9 + 7 + 5 + 3) and (8 + 6 + 4 + 2 + 1). The sums are 24 and 21, respectively. The difference is 24 - 21 = 3, which is not divisible by 11, so 987,654,321 is not divisible by 11.

Question 5

5. How can I remember the divisibility rules for 8 and 11?

Accepted Answer

Ans.A good way to remember the divisibility rule for 8 is to think of the last three digits, like a mini number check. For 11, remember to alternate sums of the digits based on their position. You can practice with various numbers to make these rules stick in your memory!

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