Hello Year 5! Today, we’re going to learn about divisibility by 3, 6, and 9. This means we’ll figure out how to tell if a number can be divided evenly by these numbers. Let’s get started!

What is Divisibility?

Divisibility is when one number can be divided by another number without leaving a remainder. For example, if we can divide 12 by 3 and get 4 with nothing left over, we say that 12 is divisible by 3.

Divisibility by 3

Key Rule: A number is divisible by 3 if the sum of its digits is divisible by 3.

Example

  • Look at the number 123.
    • Add the digits: ( 1 + 2 + 3 = 6 ).
    • Since 6 is divisible by 3, the number 123 is also divisible by 3!

Divisibility by 6

Key Rule: A number is divisible by 6 if it is divisible by both 2 and 3.

  1. Divisible by 2: A number is divisible by 2 if it ends in an even digit (0, 2, 4, 6, 8).
  2. Divisible by 3: Use the rule we learned above.

Example

  • Look at the number 24.
    • It ends in 4 (even), so it is divisible by 2.
    • Add the digits: ( 2 + 4 = 6 ) (divisible by 3).
    • Since 24 is divisible by both 2 and 3, it is also divisible by 6!

Divisibility by 9

Key Rule: A number is divisible by 9 if the sum of its digits is divisible by 9.

Example

  • Look at the number 252.
    • Add the digits: ( 2 + 5 + 2 = 9 ).
    • Since 9 is divisible by 9, the number 252 is also divisible by 9!

Tips and Tricks

  • To check for divisibility by 3 or 9, always add the digits together.
  • For 6, remember to check for both evenness (divisible by 2) and the sum of digits (divisible by 3).
  • Practice with different numbers to get better at spotting patterns!

Questions

Easy Level

  1. Is 15 divisible by 3?
  2. Is 18 divisible by 3?
  3. Is 24 divisible by 6?
  4. Is 30 divisible by 3?
  5. Is 42 divisible by 6?
  6. Is 27 divisible by 9?
  7. Is 12 divisible by 6?
  8. Is 21 divisible by 3?
  9. Is 36 divisible by 9?
  10. Is 48 divisible by 6?
  11. Is 9 divisible by 3?
  12. Is 54 divisible by 9?
  13. Is 60 divisible by 6?
  14. Is 81 divisible by 9?
  15. Is 63 divisible by 3?
  16. Is 72 divisible by 6?
  17. Is 30 divisible by 9?
  18. Is 45 divisible by 3?
  19. Is 27 divisible by 3?
  20. Is 90 divisible by 6?

Medium Level

  1. Is 123 divisible by 3?
  2. Is 156 divisible by 6?
  3. Is 81 divisible by 9?
  4. Is 234 divisible by 3?
  5. Is 390 divisible by 6?
  6. Is 888 divisible by 9?
  7. Is 465 divisible by 3?
  8. Is 546 divisible by 6?
  9. Is 729 divisible by 9?
  10. Is 912 divisible by 3?
  11. Is 105 divisible by 3?
  12. Is 462 divisible by 6?
  13. Is 234 divisible by 9?
  14. Is 306 divisible by 3?
  15. Is 513 divisible by 9?
  16. Is 978 divisible by 6?
  17. Is 333 divisible by 3?
  18. Is 234 divisible by 6?
  19. Is 486 divisible by 9?
  20. Is 672 divisible by 6?

Hard Level

  1. Is 12345 divisible by 3?
  2. Is 34560 divisible by 6?
  3. Is 987654 divisible by 9?
  4. Is 23456 divisible by 3?
  5. Is 87654 divisible by 6?
  6. Is 54321 divisible by 3?
  7. Is 111111 divisible by 9?
  8. Is 222222 divisible by 6?
  9. Is 999999 divisible by 3?
  10. Is 67890 divisible by 6?
  11. Is 13579 divisible by 3?
  12. Is 888888 divisible by 9?
  13. Is 24680 divisible by 6?
  14. Is 121212 divisible by 3?
  15. Is 555555 divisible by 9?
  16. Is 444444 divisible by 6?
  17. Is 121212 divisible by 3?
  18. Is 777777 divisible by 9?
  19. Is 999999 divisible by 6?
  20. Is 123456 divisible by 3?

Answers and Explanations

Easy Level Answers

  1. Yes
  2. Yes
  3. Yes
  4. Yes
  5. Yes
  6. Yes
  7. Yes
  8. Yes
  9. Yes
  10. Yes
  11. Yes
  12. Yes
  13. Yes
  14. Yes
  15. Yes
  16. Yes
  17. No
  18. Yes
  19. Yes
  20. Yes

Medium Level Answers

  1. Yes
  2. Yes
  3. Yes
  4. Yes
  5. Yes
  6. Yes
  7. Yes
  8. Yes
  9. Yes
  10. Yes
  11. Yes
  12. Yes
  13. No
  14. Yes
  15. Yes
  16. Yes
  17. Yes
  18. Yes
  19. Yes
  20. Yes

Hard Level Answers

  1. Yes
  2. Yes
  3. Yes
  4. Yes
  5. Yes
  6. Yes
  7. Yes
  8. Yes
  9. Yes
  10. Yes
  11. No
  12. Yes
  13. Yes
  14. Yes
  15. Yes
  16. Yes
  17. Yes
  18. Yes
  19. No
  20. Yes

Remember, practice makes perfect! Keep trying out different numbers, and you’ll get better at understanding divisibility. Happy learning!