Maths Playing with Numbers part 9 (Questions) CBSE Class 8 Mathematics VIII | Summary and Q&A

TL;DR

Learn about the divisibility rules for numbers and solve questions related to multiple of 9 and 3.

Key Insights

• 🍹 Divisibility by 9 requires the sum of the digits to also be a multiple of 9.
• 🤪 For 31z5 to be a multiple of 9, z can be either 0 or 9.
• ☺️ To find the possible values of x in 24x to make it a multiple of 3, the sum of the digits must be a multiple of 3.
• #️⃣ Divisibility rules can be used to quickly determine if a number is divisible by another number.
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Transcript

hello friends this video on playing with numbers part nine is brought to you by exam fear dot com no more fear from exam so based on whatever we have learned about the divisibility rules so far let us quickly look at a few questions question number one if 3 1 z 5 is a multiple of 9 where z is a digit what is the value of z now if this number is a m... Read More

Questions & Answers

Q: How can we determine if a number is a multiple of 9?

To check if a number is a multiple of 9, we need to find the sum of its digits. If the sum is a multiple of 9, the number is also a multiple of 9.

Q: What values can the digit z take to make 31z5 a multiple of 9?

The digit z can be either 0 or 9. If z is 0, the sum of the digits is 9, which is a multiple of 9. If z is 9, the sum becomes 27, which is also a multiple of 9.

Q: How do we determine the value of x in 24x to make it a multiple of 3?

The sum of the digits, 2 + 4 + x, should be a multiple of 3. By trying different values for x, we find that x can be 0, 3, 6, or 9.

Q: What are the divisibility rules for numbers?

Divisibility by 2, 5, and 10 depends only on the last digit. Divisibility by 4 depends on the last two digits. Divisibility by 3 and 9 depends on the sum of the digits.

Summary & Key Takeaways

• This video discusses divisibility rules and focuses on questions involving the multiples of 9.

• The sum of the digits in a number should be a multiple of 9 for the number to be a multiple of 9.

• The value of the unknown digit, z, can be 0 or 9 to satisfy the divisibility rule.