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Beginners Divisibility.pptx
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- 7. Definition of Divisibility Divisibilityrefers to a number's quality of being evenly divided by another number, without a remainder left over. For example: 63 ÷ 7 = 9 50 ÷ 10 = 5 Non examples: 79 ÷ 7 = 11 R2 39 ÷ 9 = 4 R3
- 8. Why should youlearn divisibility? Divisibility rules of whole numbers are very useful because they help us to quickly determine if a number can be divided by single digit numbers and 10 without doing long division. This is especially useful when the numbers are large.
- 9. Divisibility Rule for2 All even numbers are divisible by 2. So, all numbers ending in 0,2,4,6 or 8 can be divided by 2. Example: 34,290 Is 1827 divisible by 2?
- 10. Divisibility Rule for3 Add up all the digits in the number to find out what the sum is. If the sum can be divided by 3, the whole number can be. Example: 333 (3 + 3 + 3 = 9) and 9 is divisible by 3, so the whole number is! Is 3561 divisible by 3?
- 11. Divisibility Rule for4 Are the last two digits in your number divisible by 4? If so, the whole number is too! Example: 728 (28 is divisible by 4) so the whole number is! Is 4876 divisible by 4?
- 12. Divisibility Rule for5 Any number ending in a 5 or a 0 are always divisible by 5. Example: 1,224,325 Is 0 divisible by 5?
- 13. Divisibility Rule for6 If the number is divisible by 2 and 3 it is divisible by 6. Example: 612 (it is an even number, so it is divisible by 2) and 6 + 2 + 1 = 9 and 9 is divisible by 3. Is 108 divisible by 6?
- 14. Divisibility Rule for7 If you double the last digit and subtract it from the rest of the number and the answer is: 0 OR divisible by 7. Example: 672 (Double 2 is 4, then 67-4=63, and 63 is divisible by 7.) Is 2457 divisible by 7?
- 15. Divisibility Rule for8 If the last 3 digits are divisible by 8. Example: 1824 (824 is divisible by 8) Is 4120 divisible by 8?
- 16. Divisibility Rule for9 If the sum of the digits is divisible by 9, then the whole number is divisible by 9. Example: 999 (9 + 9 + 9 = 27) and 27 is divisible by 9, so the whole number is. Is 5364 divisible by 9?
- 17. Practice Problem Let’s tryfilling out this chart using divisibility rules
- 18. Answer Yes No NoNo Yes No No Yes No Yes No Yes No No Yes Yes No Yes No No Yes Yes No Yes Yes Yes No Yes No Yes Yes No No No No No No No Yes Yes Yes No Yes Yes No Yes Yes No Yes Yes No No Yes No Yes No Yes Yes No No Yes No No Yes No No No No No Let’s try filling out this chart using divisibility rules
- 19. Divisibility Rule for10 If a number ends in a 0, it is divisible by 10. Also if a number is divisible by both 2 and 5, it is divisible by 10 Example: 30, 55800, 67920
- 20. Review Problem: Which ofthe following numbers is divisible by 3? a)51412 b)86221 c)63693
- 21. Answer Which of thefollowing numbers is divisible by 3? c) 63693
- 22. Review Problem: Which ofthe following numbers is divisible by 6? a)39052 b)80148 c)52335
- 23. Answer Which of thefollowing numbers is divisible by 6? b) 80148
- 24. Practice Problem: There are1,728 fish in a hatchery, which are divided evenly among the ponds. How many ponds could there be at the hatchery? a)10 b)4 c)5
- 25. Answer There are 1,728fish in a hatchery, which are divided evenly among the ponds. How many ponds could there be at the hatchery? b) 4
- 26. Practice Problem Is 41295divisible by 15?
- 27. Answer If we canverify that 41295 is divisible by both 3 and 5, then it is divisible by 15. Sum of the digits in 41295 : 4 + 1 + 2 + 9 + 5 = 21 Because 21 is a multiple of 3, 41295 is divisible by 3. In 41295, the digit in one's place is 5. Therefore, 41295 is divisible by 5. Now, it is clear that 41295 is divisible by both 3 and 5. So, 41295 is divisible by 15.
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- 32. Time for handouts! Takethe handouts that you printed out at home and using the concepts that we learned today, start working on them. If you don’t finish that’s okay, you can finish it at home.