Divisibility Rules and Digit Sums

The video tutorial explains divisibility rules for the numbers 6, 9, and 10. A number is divisible by 6 if it is divisible by both 2 and 3. For 9, the sum of the digits must be divisible by 9. A number is divisible by 10 if it ends in zero. The tutorial applies these rules to two example numbers, 567 and 6210, demonstrating how to determine their divisibility by 6, 9, and 10.

What must be true for a number to be divisible by 6?

• It must end in a zero.

• It must be divisible by 2 and 3.

• It must be an odd number.

• It must be divisible by 3 and 9.

How do you determine if a number is divisible by 9?

• The sum of its digits must be divisible by 9.

• The number must end in 9.

• It must be an even number.

• It must be divisible by 3.

What is the rule for a number to be divisible by 10?

• It must be divisible by 5.

• It must be an odd number.

• It must end in a zero.

• The sum of its digits must be 10.

Which of the following numbers is divisible by 9?

• 234

• 567

• 678

• 123

Why is the number 567 not divisible by 6?

• It is not divisible by 2.

• It is divisible by 9.

• It ends in a zero.

• It is not divisible by 3.

What is the sum of the digits of 567?

• 15

• 18

• 21

• 20

Is the number 6210 divisible by 2?

• Yes, because it is divisible by 3.

• No, because it is not divisible by 9.

• No, because it ends in an odd number.

• Yes, because it ends in an even number.

What is the sum of the digits of 6210?

• 11

• 10

• 9

• 8

Why is 6210 divisible by 6?

• It is divisible by 9.

• It ends in a zero.

• It is divisible by 2 and 3.

• It is an odd number.

Which of the following numbers is divisible by 10?

• 1230

• 6210

• 5678

• 4321