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PROGRESSION THROUGH CALCULATIONS FOR DIVISION MENTAL CALCULATIONS *** Mental calculation needs to be taught for the children to become efficient*** These are a selection of mental calculation strategies: See ‘Teaching Children to Calculate Mentally’, pages 8 -11 for progression statements and pages 51 -71 for strategies to teach. Doubling and halving Knowing that halving is dividing by 2 Deriving and recalling division facts Tables should be taught everyday from Y2 onwards, either as part of the mental oral starter or other times as appropriate within the day. Year 2 Year 3 Year 4 Year 5 & 6 2 times table, 5 times table, 10 times table 2 times table, 3 times table, 4 times table, 5 times table 6 times table, 10 times table Derive and recall division facts for all tables up to 10 x 10 Derive and recall quickly division facts for all tables up to 10 x 10 Using and applying division facts Children should be able to utilise their tables knowledge to derive other facts. e.g. If I know 3 x 7 = 21, what else do I know? 30 x 7 = 210, 300 x 7 = 2100, 3000 x 7 = 21 000, 0.3 x 7 = 2.1 etc Dividing by 10 or 100 Knowing that the effect of dividing by 10 is a shift in the digits one place to the right. Knowing that the effect of dividing by 100 is a shift in the digits two places to the right. Use of factors 378 ÷ 21 378 ÷ 3 = 126 126 ÷ 7 = 18 378 ÷ 21 = 18 Use related facts Given that 1.4 x 1.1 = 1.54 What is 1.54 ÷ 1.4, or 1.54 ÷ 1.1? MANY MENTAL CALCULATION STRATEGIES WILL CONTINUE TO BE USED. THEY ARE NOT REPLACED BY WRITTEN METHODS. *Please see vocabulary book THE FOLLOWING ARE STANDARDS THAT WE EXPECT THE MAJORITY OF CHILDREN TO ACHIEVE. Foundation Phase Until children are ready for written calculation, they need to have a secure understanding of: Number - recognise, count, order, write and use numbers up to 10 (progression up to 20). Vocabulary related to division as sharing* Counting in ones, twos, and tens. Recognising and understanding equal sized groups During all of these play based activities teachers and staff will support children’s developing knowledge by representing quantities (at first) and then calculations (not using the division symbol, but as repeated subtraction), either by drawing pictures or symbols or by writing numerals. Children develop ways of recording calculations, using pictures. Lower Phase Children will understand equal groups and share items out in play and problem solving. They will count in 2s and 10s and later in 5s. Children will use vocabulary related to division* *Please see vocabulary book Children will develop their understanding of division and use jottings to support calculation Sharing equally 6 sweets shared between 2 people, how many do they each get? Grouping or repeated subtraction There are 6 sweets, how many people can have 2 sweets each? Repeated subtraction using a number line or bead bar 12 ÷ 3 = 4 0 1 2 3 4 3 5 6 7 3 8 9 10 11 12 3 3 The bead bar will help children with interpreting division calculations such as 10 ÷ 5 as ‘how many 5s make 10?’ Therefore beginning to relate division to the inverse, multiplication. Using symbols to stand for unknown numbers to complete equations using inverse operations ÷2=4 *Please see vocabulary book 20 ÷ = 4 ÷=4 Repeated subtraction using a number line or bead bar with remainders 13 ÷ 3 = 4 remainder 1 or r1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 Middle Phase Ensure that the emphasis in Y3 is on grouping rather than sharing. Children to use the vocabulary related to division* Children will continue to use: Repeated subtraction using a number line Children will use an empty number line to support their calculation. 24 ÷ 4 = 6 0 4 8 12 16 20 24 Children should also move onto calculations involving remainders, using an empty number line. 13 ÷ 4 = 3 r 1 0 1 5 9 13 Using symbols to stand for unknown numbers to complete equations using inverse operations 26 ÷ 2 = 24 ÷ = 12 ÷ 10 = 8 Children will develop their use of repeated subtraction to be able to subtract multiples of the divisor. Initially, these should be multiples of 10s, 5s, 2s and 1s – numbers with which the children are more familiar. 72 ÷ 5 0 2 -5 7 12 -5 17 -5 *Please see vocabulary book 22 -5 -5 27 32 37 -5 -5 -5 42 47 52 -5 -5 -5 57 62 -5 67 -5 -5 72 Moving onto: 02 r2 1 -5 7 1 -5 12 1 17 -5 1 22 -5 10 -50 (10x 5) (1x 5) (1x 5) (1x 5) (1x 5) Then onto the vertical method (Chunking): TU ÷ U 72 ÷ 3 3 ) 72 - 30 42 - 30 12 6 6 6 0 Answer : 10x3 10x3 2x3 2x3 24 Leading to subtraction of other multiples. 96 ÷ 6 16 6 ) 96 - 60 36 - 36 0 Answer : 10x6 6x6 16 Any remainders should be shown as integers, i.e. 14 remainder 2 or 14 r 2. Children need to be able to decide what to do after division and round up or down accordingly. They should make sensible decisions about rounding up or down after division. For example 62 ÷ 8 is 7 remainder 6, but whether the answer should be rounded up to 8 or rounded down to 7 depends on the context. *Please see vocabulary book e.g. I have 62p. Sweets are 8p each. How many can I buy? Answer: 7 (the remaining 6p is not enough to buy another sweet) Apples are packed into boxes of 8. There are 62 apples. How many boxes are needed? Answer: 8 (the remaining 6 apples still need to be placed into a box) Upper Phase Children will use vocabulary related to division* Children will continue to use written methods to solve division TU ÷ U. Children can start to subtract larger multiples of the divisor, e.g. 30x HTU ÷ U 196 ÷ 6 32 r 4 6 ) 196 - 180 30x 6 16 12 2x 6 4 Answer : 32 remainder 4 or 32 r 4 Any remainders should be shown as integers, i.e. 14 remainder 2 or 14 r 2. Children need to be able to decide what to do after division and round up or down accordingly. They should make sensible decisions about rounding up or down after division. For example 240 ÷ 52 is 4 remainder 32, but whether the answer should be rounded up to 5 or rounded down to 4 depends on the context. Children will continue to use written methods to solve division TU ÷ U and HTU ÷ U. Then moving onto: HTU ÷ TU 972 ÷ 36 27 36 ) 972 - 720 252 - 252 0 Answer : *Please see vocabulary book 20x 36 7x 36 27 Any remainders should be shown as fractions, i.e. if the children were dividing 32 by 10, the answer should be shown as 3 2/10 which could then be written as 3 1/5 in it’s lowest terms. Extend to decimals with up to two decimal places. Children should know that decimal points line up under each other. 87.5 ÷ 7 7) - 12.5 87.5 70.0 17.5 14.0 3.5 3.5 0 10x 2x 0.5x Answer : 12.5 The children should also be taught that when dividing a number by a single digit they might decide to use the short division method 875 ÷ 7= 125 7)875 3 1 This method can also be used to when finding a decimal fraction as an answer 362 ÷ 8 = 45.25 0 4 5. 2 5 8 ) 3 6 2. 0 0 3 *Please see vocabulary book 4 2 4