#### Transcript gumbers - Clapham Terrace

I think of a number and add 6. My answer is negative 7, what number did I start with? Sums and Things for Parents Monday 19th March Clapham Terrace Primary School Negative 13 Well done Lucie. How did you think that through? Sums and Things for Parents The story so far at Clapham children’s 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! 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 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 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. Learning written methods is not the ultimate aim. Mathematics is foremost an activity of the mind, and written calculations are an aid to that mental activity. At Clapham our aim is to develop children’s mental strategies and then written methods that derive from and support mental methods. We want children at Clapham 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? How do you add and subtract? 76 + 47 * 358 + 473 7800 – 5600 * 5735 + 3990 43 – 24 * 5002 – 4996 8.23 – 4.55 * 267 + 267 2.5 + 2.7 5.1 - 2.78 Addition 76 + 47 = +10 76 +10 86 +10 96 +10 106 +7 116 + 40 76 123 +7 116 123 Addition 358 + 473 = 358 358 + 473 + 473 11 120 831 700 831 1 1 Addition – using partition 176 + 147 = 100 + 70 + 6 + 100 + 40 + 7 200 + 110 + 13 = 323 Subtraction Imran has 43 conkers; he gives 24 away to his friends. How many does he have left? 43 – 24 = 19 20 -1 19 conkers 23 -3 33 -10 43 -10 Subtraction Sam has saved 93p, Amy has 55p. How much more money does Sam have than Amy? 93 – 55 = +5 55 38p more +30 60 +3 90 93 Subtraction 8.23 – 4.55 = +0.45 4.55 3.68 5.00 +3 +0.23 8.00 8.23 Subtraction A sports stadium holds 9010 spectators. 5643 people attend a football match. How many empty seats are there? + 57 5643 5700 +300 +3010 6000 9010 5643 3367 empty seats 5700 6000 9010 57 +300 +3010 3367 How do you multiply and divide? 47 x 8 * 47 ÷ 8 * 37 x 46 * 375 ÷ 43 * 36 x 25 700 ÷ 4 18 x 15 65.5 10 8 x 19 17 ÷ 5 34 x 7 5.4 ÷ 6 Multiplication 47 x 8 = x 8 40 320 7 56 30 1200 180 7 280 42 376 37 x 46 = x 40 6 1480 222 1702 ……… leading to algebra at KS3 (a + b) 2 = (a + b) x (a + b) x a b a 2 a ab b ab 2 b 2 a + ab 2 ab + b 2 a + 2ab + b (a + b) 2 2 = a + 2ab + b 2 2 Division 47 8 375 43 8 47 43 375 …or ‘chunking’ First on a number line 3 87 ÷ 7 17 87 -14 subtract 7x2 or 7 twice -70 subtract 7x10 or 7 ten times We have subtracted seven 12 times and have 3 left so… 87 ÷ 7 = 12 r 3 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 it’s 12 weeks (and 3 days) of shopping to Christmas. 432 school children are going on an outing. If each bus takes 15 passengers, how many buses will be needed? 432 -300 132 (20 buses) - 90 (6 buses) 42 -30 (2 buses) 12 (people left) So we need 29 buses or 28 buses and some cars! 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!