Division Using multiplication and traditional short division Whats

Division Using multiplication and traditional short division

What’s It All About? You are going to learn: How to divide by inversing multiplication and using traditional short division. What skills should you have already? You need to be able to multiply and subtract two values using a written method.

Division Remember that 6 ÷ 3 means “how many threes make 6? ” Division is the INVERSE of Multiplication. There are different ways of showing division. 6÷ 3 The answer is the same in all three cases!

Using Multiplying to Divide For multiplying, we can use a grid like this: 2 3 4 1 2 3 4 2 4 6 8 3 4 5 6 7 8 9 6 8 10 12 14 16 18 9 12 15 18 21 24 27 12 16 20 24 28 32 36 5 6 10 15 20 25 30 35 40 45 12 18 24 30 36 42 48 54 We can now use it to divide as well as multiply. Example: 20 4 means “How many 4’s make 20? ” The answer is 5

Your Turn Remember that 6 ÷ 3 means “how many threes make 6? ” Work out: 1. 16 ÷ 4 2. 30 ÷ 5 3. 30 ÷ 10 4. 45 ÷ 9 5. 72 ÷ 8 6. 21 ÷ 3 7. 21 ÷ 7

Traditional Short Division 1 Find the answer to £ 84 ÷ 4 How many 4’s make 84? Set up the division: 2 1 You have 8 ten pound notes to share between 4 people. How many do they get each? You have 4 one pound coins to share between 4 people. How many do they each get? £ 84 ÷ 4 = 21

Traditional Short Division 2 Work out 312 ÷ 12 How many 12’s make 312? Set up the division: 2 3 You have 3 one hundred pound notes to share between 12 people. Can you share out the notes? No Change them into ten pound notes. . . This question is not about money, but it is easier if you think of it in that way. . . You have 31 ten pound notes to share between 12 people. How many do they each get? 12 2 = 24 and 12 3 = 36 How many notes are left? 31 – 24 = 7

Traditional Short Division 2 Work out 312 ÷ 12 Set up the division: 2 6 37 How many notes are left? 31 – 24 = 7 Change them into one pound coins. You have 72 one pound coins to share between 12 people. How many do they each get? 12 6 = 72 312 ÷ 12 = 26

Traditional Short Division 3 Work out 484 ÷ 11 How many 11’s make 484? Set up the division: 4 4 You have 4 one hundred pound notes to share between 11 people. Can you share out the notes? No Change them into ten pound notes. . . You have 48 ten pound notes to share between 11 people. How many do they each get? 11 4 = 44 and 11 5 = 55 How many notes are left? 48 – 44 = 4

Traditional Short Division 3 Work out 484 ÷ 11 How many 11’s make 484? Set up the division: 4 4 Change them into one pound coins. You have 44 one pound coins to share between 11 people. How many do they each get? 11 4 = 44 484 ÷ 11 = 44 How many notes are left? 48 – 44 = 4

Your Turn Remember that 6 ÷ 3 means “how many threes make 6? ” Work out: 1. 728 ÷ 8 2. 219 ÷ 3 3. 21749 ÷ 7 4. 384 ÷ 12 5. 2190 ÷ 10 6. 273 ÷ 13 7. 2310 ÷ 11

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