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L.O.1 To be able to identify factor pairs of small 2-digit numbers

L.O.1 To be able to identify factor pairs of small 2-digit numbers. 36 A factor is a number that goes into another exactly. One factor of 36 is 9, what is its pair? Write the other factor pairs of 36. Factor pairs of 36 are: 9 x 4 = 36 3 x 12 = 36 18 x 2 = 36

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L.O.1 To be able to identify factor pairs of small 2-digit numbers

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  1. L.O.1 To be able to identify factor pairs of small 2-digit numbers

  2. 36 A factor is a number that goes into another exactly. One factor of 36 is 9, what is its pair? Write the other factor pairs of 36.

  3. Factor pairs of 36 are: 9 x 4 = 36 3 x 12 = 36 18 x 2 = 36 1 x 36 = 36 6 x 6 = 36 The number 36 is special as one factor pair has two identical numbers - 6 x 6. Q. What do we call numbers like 36?

  4. 36 is a square number.

  5. In your book write the factor pairs for : 40 24 64 Two minutes

  6. L.O.2 To be able to use factors as a strategy for mental multiplication.

  7. LOOOOOK! 4 X 3 X 5 Q. How would you work this out in your head?

  8. The operation of multiplication is commutative….. a sum can be done in different ways. 4 x 3 x 5 e.g. 4 x 3 = 12 x 5 = 60 4 x 5 = 20 x 3 = 60 3 x 5 = 15 x 4 = 60 The answer is the same whichever way you do it.

  9. Try doing these in different ways in your books. • 15 x 3 x 2 • 2 x 3 x 4 x 5 Four minutes

  10. LOOOOOOK! 17 x 12 This may look hard but isn’t once we find the factors. Q. What factors can we find for 17 and 12

  11. 17 x 12 = 17 x 3 x 2 x 2 Q. How does this make the calculation easier?

  12. We can multiply 17 by 3 then double and double. e.g. 17 x 12 17 x 6 x 2 17 x 3 x 2 x 2 = 51 x 2 x 2 = 102 x 2 = 204

  13. Work in pairs and use this method to find answers to : 23 x 6 17 x 4 19 x 8 Not long

  14. 26 x 6 To help us do this sum we will find factor pairs for each number. 26 x 6 = ( 2 x 13 ) x ( 2 x 3 ) = 3 x 13 x 2 x 2 = 39 x 2 x 2 = 78 x 2 = 156

  15. Let’s try : 34 x 6

  16. Calculations for you to do in the same way : Prisms : 14 x 8 ; 23 x 6 ; 24 x 9 ; 18 x 22 16 x 9 ; 27 x 12 Spheres: 15 x 9 ; 11 x 12 ; 14 x 6 ; 16 x 8 Tetrahedrons: 14 x 8 ; 16 x 6 ; 13 x 15

  17. Here’s one to do as a class….. 22 x 18

  18. By the end of the lesson children should be able to: Use factors to carry out multiplication mentally.

  19. L.O.1 To be able to order a set of positive and negative integers

  20. Copy this number line into your books: 0 -20 +20

  21. We need 6 numbers which will fit somewhere on your line. The numbers are : Put the numbers in the correct place on your line.

  22. If we change the sign for each number so that positive numbers become negative and negative numbers become positive we get : Q. How will the numbers change on the number line? A. ……. Draw a new number line and insert the new numbers.

  23. The new numbers become a reflection about 0. Loooooook! Mirror -6 6 -20 20 0

  24. Draw another number line and put in these numbers: -14 ; 8 ; -9 ; 10 ; 3 ; -17 . Now change the signs and insert the new numbers – use a different colour. Check your partner’s! 4 minutes

  25. L.O.2 To be able to solve simple word problems. To begin to use brackets.

  26. Fish £2 Chips £1 Q. I have just spent £9. What could I have bought? Q. How many fish could I have bought?

  27. A good way to sort all the possibilities is like this: Fish 0 1 2 3 4 Chips 9 7 5 3 1 You can see there are 5 possible combinations.

  28. Try this: Cola 50p. Pizza £1:50 Q. If I spend £8 what could I buy? Record your working in the same way as the problem we have just done. Q. How many possible combinations are there?

  29. Create a similar problem for the other pairs on your table to answer. 5 minutes

  30. Let’s go back to our first problem Fish £2 : Chips £1 A child goes to the chip shop and asks for “Two fish and chips”. The owner asks for £6. but the child expects to be charged only £5. Q. Can you explain why?

  31. “ two ( fish and chips)” : “ ( two fish ) and chips” Q. What is the difference between the two statements? Using brackets can help us solve the problem. 2 x ( £2 + £1) : ( 2 x £2 ) + £1 The brackets help remove confusion.

  32. REMEMBER THE STEP IN BRACKETS IS ALWAYS DONE FIRST !

  33. compare 6 + 3 – 2 6 – 3 + 2 Q. How would you work out this calculation? Consider these: (6 + 3) – 2 = 7 6 + ( 3 - 2 ) = 7 9 - 2 = 7 6 + 1 = 7 compare: 6 – 3 + 4 = ? 6 – 3 + 2 = ? (6 – 3) + 4 = 5 6 – ( 3 + 2 ) = 1 6 - ( 3 + 4) = -1 (6 – 3 ) + 2 = 5

  34. We will try to get as close to a target number as we can using 3 digits, 5 signs and some brackets. Target Number = 30 Digits are 6 ; 4 ; and 1. (6 x 4)+1=25 (6-1)x4=20 (6+1)x4=28 6 x (4+1)=30

  35. With a partner choose a target number between 20 and 50. Use 3 rolls of the die to give you the digits you need. Get as close to your target number as you can. Record your attempts in your book. Prisms : 4 different target numbers. Circles : 3 different target numbers. Tetrahedra : 2 different target numbers. 5 minutes maximum

  36. Try these in your book: 4 + 2 x 3 4 + 2 + 3 4 x 2 x 3 4 – 2 x 3 You can use brackets anywhere. Q. Which calculation could give the biggest / smallest answer? Why?

  37. By the end of the lesson children should be able to: Use brackets, Solve simple word problems by listing.

  38. L.O.1 To be able to use doubling and halving starting from known facts.

  39. 7 Double this ad infinitum.

  40. Now halve the last number!

  41. 24 x 4 = 24 x 2 x 2 Q. How can we work out the answer to 24 x 4 using the above statement? A. …… 48 X 2

  42. To multiply by 4 we use doublingthen doublingagain. As 2 is a factor of 4 this method is really using factors. 560 ÷ 4 Q. How can we work this out?

  43. (560 ÷ 2) ÷ 2 Dividing by 2 is the same as halving and halving again. Look : 560 ÷ 2 = 280 280 ÷ 2 = 140

  44. L.O.2 To be able to use all four operations to solve simple word problems. To begin to use brackets.

  45. 1. 48 ÷ 8 2. 43 + 27 + 12 +17 3. 617 – 322 4. (33 – 18) x 2 5. 23 – 17 6. (3 + 5) x 2 7. ( 12 ÷ 2 ) x 2 8. 36 ÷ ( 4 + 2 ) Brackets always indicate the first stage of a calculation. Q. In a class of 33 children, 18 had no pets, the others had two pets each. How many pets is that? Which calculation from those shown would you use to solve this problem?

  46. 1. 48 ÷ 8 2. 43 + 27 + 12 +17 3. 617 – 322 4. (33 – 18) x 2 5. 23 – 17 6. (3 + 5) x 2 7. ( 12 ÷ 2 ) x 2 8. 36 ÷ ( 4 + 2 ) With a partner work out some word- based problems for which the other calculations on the board will be the solutions : Prisms – do all 7 Spheres – do at least 5 Tetrahedra – do at least 3 10 minutes

  47. A. ….. Read problems aloud. Q. Which calculation matches the word problem? How did you decide?

  48. Work out a calculation ON YOUR OWN using all four operations and develop a word problem from it. Make it as interesting as possible. A. ……

  49. The answer to a problem is “ 37 legs”. With a partner make up an interesting word problem which has this answer.

  50. By the end of the lesson children should be able to : Solve “story problems about numbers in real life, choosing the appropriate operation and method of calculation. Explain and record using numbers, signs and symbols how the problem was solved.

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