Divisibility Rules and Digit Sums

The video tutorial by Mr. J explains the divisibility rule for 9. It states that if the sum of a number's digits is divisible by 9, then the number itself is divisible by 9. The video provides examples with numbers 107, 162, and 9414 to illustrate the rule. 107 is not divisible by 9 as its digits sum to 8, while 162 and 9414 are divisible as their digits sum to 9 and 18, respectively. The tutorial concludes with a prompt to check the description for a more detailed explanation.

What is the first step in determining if a number is divisible by nine?

• Add the digits together

• Subtract the digits from each other

• Divide the number by nine

• Multiply the digits together

Why is the number 107 not divisible by nine?

• The sum of its digits is 8

• The sum of its digits is 7

• The sum of its digits is 9

• The sum of its digits is 10

What is the sum of the digits of 162, and is it divisible by nine?

• The sum is 8, and it is not divisible by nine

• The sum is 9, and it is divisible by nine

• The sum is 10, and it is not divisible by nine

• The sum is 12, and it is divisible by nine

For the number 9414, what is the sum of its digits?

• The sum is 18

• The sum is 19

• The sum is 20

• The sum is 21

What conclusion can be drawn about the number 9414 based on the divisibility rule for nine?

• 9414 is not divisible by nine

• 9414 is a prime number

• 9414 is divisible by nine

• 9414 is divisible by three