I think of a number and add 6. My answer is negative 7, what number did I start with? Sums and...

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Transcript of I think of a number and add 6. My answer is negative 7, what number did I start with? Sums and...

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I think of a number and add 6. My answer is negative 7, what number did I start with? Sums and Things for Parents Slide 2 Well done Lucie. How did you think that through? Sums and Things for Parents Negative 13 Slide 3 The story so far . childrens recall of number facts has become more accurate and faster children are more aware of the strategies they use to calculate they use vocabulary correctly they are more confident about maths maths is more fun! Slide 4 What can a numerate child do? By the age of 11 they should : have a sense of the size of number and where it fits into the number system know by heart addition and subtraction facts to 20, multiplication and division facts to 10x10, doubles and halves, complements to 100, multiply and divide by 10 and 100 use what they know to figure out answers mentally Slide 5 What can a numerate child do? (cont.) calculate accurately and efficiently, both mentally and on paper, using a range of strategies recognise when it is appropriate to use a calculator- and when it is not- and be able to use one effectively explain their methods and reasoning using correct mathematical terms judge whether their answers are reasonable and have strategies for checking them where necessary Slide 6 The aim The aim is for children to do mathematics in their heads, and if the numbers are too large, to use pencil and paper to avoid losing track. To do this children need to learn quick and efficient methods, including appropriate written methods. Slide 7 Mathematics is foremost an activity of the mind, and written calculations are an aid to that mental activity. The Numeracy Strategy aims to develop childrens mental strategies and then written methods that derive from and support mental methods. Learning written methods is not the ultimate aim. Slide 8 We want children to ask themselves: Can I do this in my head? Can I do this in my head using drawings or jottings? Do I need to use an expanded/compact written method? Do I need a calculator? Slide 9 61 + 457800 5600 5735 + 36575735 + 3990 83 685002 4996 538 - 295267 + 267 2.5 + 2.75.1 - 2.78 How do you add and subtract? Slide 10 16 - 9 1 Mistakes children make: Slide 11 643 + 274 8117 803 - 526 187 .and more: 6 1013 Slide 12 76 + 47 = 76 Addition 116 76 + 40 123 + 7 86 +10 96 +10 106 +10 116 +10 123 +7 Slide 13 358 + 473 = Addition 358 + 473 11 120 700 831 358 + 473 831 11 Slide 14 100 + 70 + 6 + 100 + 40 + 7 200 + 110 + 13 = 323 176 + 147 = Addition Slide 15 Subtraction Imran has 43 conkers; he gives 24 away to his friends. How many does he have left? 43 24 = 4333 -10 23 -10 20 -3 19 19 conkers Slide 16 Subtraction Sam has saved 93p, Amy has 55p. How much more money does Sam have than Amy? 93 55 = 55 60 +5 93 +3 90 +30 38p more Slide 17 Subtraction 8.23 4.55 = 3.68 8.23 8.00 5.00 4.55 +0.23 +3+0.45 Slide 18 Subtraction A sports stadium holds 9010 spectators. 5643 people attend a football match. How many empty seats are there? 5643 5700 6000 9010 57 +300 +3010 3367 564357009010 + 57+300+3010 3367 empty seats 6000 Slide 19 57 x 278 2 43 x 50 742 2 36 x 25 700 4 18 x 15 65.5 10 8 x 1917 5 34 x 75.4 6 How do you multiply and divide? Slide 20 Mistakes children make: 76 x 8 5648 67 x 54 268 335 603 101 r 5 7 847 Slide 21 Multiplication 47 x 8 = x 407 8 32056376 37 x 46 = x 30 7 40 1200 280 1480 6 180 42 222 1702 Slide 22 leading to algebra at KS3 xab aa 2 aba 2 + ab babb 2 ab + b 2 a 2 + 2ab + b 2 (a + b) 2 = (a + b) x (a + b) (a + b) 2 = a 2 + 2ab + b 2 Slide 23 Division 375 43 43 375 47 8 8 47 Slide 24 or chunking Slide 25 First on a number line 87 7 17873 subtract 7x10 or 7 ten times We have subtracted seven 12 times and have 3 left so 87 7 = 12 r 3 subtract 7x2 or 7 twice -70 -14 Slide 26 A shop notice states that there are 87 shopping days to Christmas. How many weeks is that? 87 -70 (10 weeks) 17 -14 (2 weeks) 3 So its 12 weeks (and 3 days) of shopping to Christmas. Slide 27 432 school children are going on an outing. If each bus takes 15 passengers, how many buses will be needed? 432 -300 (20 buses) 132 - 90 (6 buses) 42 So we need 29 buses or 28 buses and some cars! -30 (2 buses) 12 (people left) Slide 28 How can you help? Talk about how you do maths Give praise and encouragement Be positive Ask your child to explain Make sure maths is fun!