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# 100’s

100’s. Properties of Number. Divisibility tests. 25’s. 4’s. Chris Clements. &lt;date&gt;. Learning Objective:. &lt;Steps to success&gt;. Divisibility Tests. In this lesson you will learn divisibility tests for multiples of 4, 25 and 100. Divisibility tests help us

## 100’s

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1. 100’s Properties of Number Divisibility tests 25’s 4’s Chris Clements

2. <date> Learning Objective: <Steps to success>

3. Divisibility Tests In this lesson you will learn divisibility tests for multiples of 4, 25 and 100. Divisibility tests help us identify if a whole number is in a specified times table e.g. Is 1272 in the 4 times tables (is it a multiple of 4)?

4. Divisibility Tests Lets see if we can find a divisibility test to see if 1272 is in the 4 times tables (is it a multiple of 4)? Can you remember learning a divisibility test for multiples of 2? All multiples of 2, are even and end with a 0, 2, 4, 6 or 8. Knowing this will help find a divisibility test for multiples of 4. Any ideas?

5. Look at the first 10 multiples of 2. 2, 4, 6, 8, 10, 12, 14, 16, 18, 20 Every other number is a multiple of 4 What do we know so far? • all multiples of 4 are even • if you half a multiple of 4 the answer is always a multiple of 2 • 100, 200, 300.. are all multiples of 4 How do we know the last point is true? Why is it important?

6. It is important to make the divisibility test less complicated. Look; If we look at the last 2 digits of any given whole number e.g. 1272 72 It’s even (so it is definitely a multiple of 2) 36 It’s still even so it must be a multiple of 4 If we half it;

7. Divisibility Tests Divisibility test for multiples of 4 Look at the last 2 digits; are they even; if so when you half them are they still even. Give it a go; 157 157 172 1,932 848 2,680 1,050 1,050 704 328 328 9,996

8. Divisibility Tests Do you know a divisibility test for multiples of 25? Lets have a look at the first eight multiples of 25. 25, 50, 75, 100, 125, 150, 175, 200 What do you notice? 25, 50, 75, 100, 125, 150, 175, 200 The tens and unit digit end in; 00, 25, 50, 75 and so on…

9. Divisibility Tests Lets find multiples of 25 by doing the divisibility test; ends with a 00, 25, 50, 75. 601 601 2, 456, 075 2,650 1, 450 32, 475 180, 000 18, 000 925 3, 535 3, 535 1,600 5,099 5,099

10. Divisibility Tests Do you know a divisibility test for multiples of 100? Lets have a look at the first eight multiples of 5. 100, 200, 300, 400, 500, 600, 700, 800 What do you notice? 100, 200, 300, 400, 500, 600, 700, 800 The last two digits are 00. So the test could be whole numbers ending in 00.

11. Divisibility Tests Lets find multiples of 100 by doing the divisibility test whole numbers ending in 00. 900 3, 567, 600 2, 500 1, 400 32, 600 99, 900 64, 700 801 801 5,000 1,400 6,008 6,008

12. Divisibility tests for multiples of 4, 25 and 100 • For multiples of 4; are the last 2 digits even; if you half the last 2 digits is the answer still even. • For multiples of 25; whole numbers ending in 00, 25, 50, 00. • For multiples of 100; whole numbers ending in 00. Divisibility tests Steps to success

13. Activity <type here>

14. Plenary 25 50 75 100 125 150 175 A number sequence starts 25, 50… which of the following numbers will be in the sequence? 1075 1075 3035 7400 7400 955 995 Is this true? Explain if you know All numbers that end in 4 are multiples of 4

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