* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Calculation Policy - Multiplication
Law of large numbers wikipedia , lookup
Large numbers wikipedia , lookup
Mechanical calculator wikipedia , lookup
Approximations of π wikipedia , lookup
Mathematics of radio engineering wikipedia , lookup
History of logarithms wikipedia , lookup
Positional notation wikipedia , lookup
Elementary mathematics wikipedia , lookup
Location arithmetic wikipedia , lookup
Northway Community Primary School Written Calculation Policy 2014 MULTIPLICATION Place value skills needed Method Expectation STAGE 1: Practical repeated addition (end of EYFS) Talk about groups of objects Talk about sharing Use appropriate vocabulary – groups of, lots of. Make sets of equal objects ‘We are making gingerbread men. How many sweeties will we need for the eyes? 1 2 \ / 3 4 \ / 5 6 \ / Link to practical problem solving activities involving equal sets of groups/role play situations e.g. How many socks on 2 children? Let’s count them. (Stick post-its for numbers on each leg.) STAGE 2: Practical and pictorial arrays towards grid (end of KS1) Understand the concept of equal grouping Doubles to 15 Knowing X means groups of Understand double means x2. Count up and back in 2s 3s 5s 10s Recognise and talk about an array Jump on equal steps along a numbered number line Count on using Counting in 2s 3s 5s 10s 3 groups of 2 = 6 Repeated addition 2+2+2+2+2 =10 5 x 2 = 10 Chanting 2x table 2 x 5 = 10 3x table 5x table 10x table Know that multiplication can be done in any Represent repeated addition and arrays as multiplication. Use practical and informal written methods and related vocabulary to support multiplication Northway Community Primary School Written Calculation Policy 2014 a number line order 2x5 = 5x2 Arrays and multiplication as repeated addition. Number patterns – jumping in 3s and 4s Word problems – There are 6 boxes. Each box has 10 pencils. How many pencils are there? STAGE 3: Grid method and short expanded column method (end of LJ) Know the result Use practical and 17 of X by 0 and 1 informal written 4x 17 x 4 = Understand methods to multiply place value (can two digit numbers by a partition TU) X 10 7 one digit number (13 X Know by heart 4) – target X tables 2,5,10 X facts 4 40 28 Lock in the zero Understand that and related multiplication is the division inverse of division. Understand zero Derive and record as a place holder = 40 + 28 = 68 related X sentences. Know how to X 2 digit numbers by Missing numbers X = 376 x 4 = 10 TU X U (teen numbers Double 2 digit eg 19 x 4) numbers (multiples of 5 and 10) Know the result of a multiplication will be bigger and is called the product. X 300 70 6 4 1200 280 24 1200 280 24 + 1504 Develop and use written Northway Community Primary School Written Calculation Policy 2014 Multiply 2 and 3 digit numbers mentally by 10 and 100 Know by heart all multiplication facts up to 12 x 12. Use known facts to calculate unknown Explain mental X strategies orally Add 2/3 digit numbers 17 14 x X 10 4 10 100 40 17 x 14 = 7 70 28 methods to record, support and explain multiplication up to HTU x U. 170 + 68 238 Repeat with HTU x TU Multiply the units first. 24 3x 1 2 60 (3 x 4) (3 x 20) 72 1 2 4 3x 1 2 6 0 3 0 0 2 7 2 ( 3 x 4) (3 x 20) (3 x 100) STAGE 4: Short expanded column (multiplying by units only) (end of UJ) As above 24 3 x 7 2 1 Progress to: 1241 3x 3723 1 Northway Community Primary School Written Calculation Policy 2014 STAGE 5: Long column Understand place value of decimals to 2 places Know by heart all X facts to 12 x 12 Relate 8 X 7 = 56 to 8 X 0.7 = 5.6 X 2/3 digit multiples of 10 mentally eg 20 X 50 Use column addition Refine and use efficient written methods to multiply HTU X U HTU x TU THTU X TU In the examples given, it is also correct to multiply starting with the tens digit (ie multiplying by the most significant digit first) Mentally multiply decimals by multiplying the decimal number by 10 to make a whole number, then dividing the answer by 10. Use efficient written methods to multiply integers and decimals by a one digit integer and to multiply: HTU X TU 1.7 x 4 = X 1 0.7 4 4 2.8 (7 x 4) ÷ 10 = 4 + 2.8 = 6.8 4.92 x 3 x 4 0.9 0.02 3 12 2.7 0.06 12 + 2.7 + 0.06 14.76