Divisibility

a. Rules for number 2,3 4, 5, 6, 8, 9 & 10
 * 1. Read over the rules for divisibility**
 * A number is __divisible by 2__ if it is an even number
 * A number is __divisible by 3__ if the sum of the digits is divisble by 3. //e.g. 198 is divisible by 3 since 1 + 9 + 8 = 18 and 18 is divisble by 3//
 * A number is __divisible by 4__ if the last two digits are divisble by 4 //e.g. 248 is divisible by 4 since 48 is.//
 * A number is __divisible by 5__ if its last digit is 0 or 5
 * A number is __divisible by 6__ if it is divisible by 2 and 3
 * A number is __divisible by 8__ if half of it is divisble by 4 //e.g. Half of 432 = 216. 216 is divisible by 4 so 432 is divisble by 8.//
 * A number is __divisible by 9__ if the sum of its digits is divisible by 9 //e.g. 279 is divisible by 9 since 2 + 7 + 9 = 18 and 18 is divisble by 9//
 * A number is __divisible by 10__ if the last digit is 0.

b. More complicated rules apply for divisibility by 7 and 11. //* try the method with some of these numbers: 112, 154, 182, 511, 994, 1078, 1274, 1274, 1757, 2051, 2464, 2513, 2520, 6223, 6447, 11823, 16506﻿//
 * You can check if a number is __divisible by 7__ by removing the units digit of the number, subtracting twice this digit and repeating until you get a smaller number that you know is divisible by 7 //e.g. to test 6146 we subtract 12 from 614 = 602 (12 is twice the units digit), and repeat the step to get 60-4 = 56. I know 56 is divisble by 7//
 * A number is divisible by 11 if the sum of the numbers made by pairing from the right is divisible by 11 //e.g. 572 paired and added is 72 + 5 = 77, which is divisble by 11; 284669 paired and added is 69 + 46 + 28 = 143, and 143 paired and added is 43 + 1, which is divisible by 11.//


 * 2. The 'Is it divisible by...?' game:**
 * [|14.Is this divisible by.pptx] - Using the methods above work out whether the number is divisible by the number in red.


 * 3. Into your books - date, title and underline them...**
 * Complete question 1 & 2 on page 44.
 * Question 2: [|How do we check divisibility by bigger numbers.pptx]
 * //Extra Challenge:// Review 3
 * //Extra, Extra Challenge:// Read ahead about prime numbers in preparation for next lesson (pages 46 & 47)


 * 4. Puzzle:** [|Divisibility Puzzle.pptx]


 * 5. Textbook exercises**
 * Now have a go at exercises 3-5


 * 6. Review**
 * [|Review of Divisibility exercise on P.44.pptx]


 * Student Resources**
 * [|7PWS07.PDF]
 * [|7PHS023.PDF]


 * Teacher Resources**
 * [|7PAP02.PDF]
 * [|7PTN02.pdf]