Calculations Year 2 What We Do and How We Do It

Transcription

1 Calculation Policy Calculations Year 2 What We Do and How We Do It

2 The following calculation policy has been devised to meet requirements of the calculation strand of the National Curriculum 2014 for the teaching and learning of mathematics. It is also designed to give pupils a consistent and smooth progression of learning in calculations across the school and through home learning. Age-related expectations: The calculation policy is organised according to age related expectations as set out in the National Curriculum Although there is an expectation that each child should aim to meet the age-related stage by the end of the year, if a child has a particular special educational need, this may affect the stage they are working at during the academic year. Once children have reached their age related expectation they will be challenged to provide explanations for their answers and develop a sense of reasoning. This is known as mastery. The correct use of mathematical vocabulary is an important part of achieving age-related expectations and children must be able to explain their mathematical thinking to achieve the age-related expectation. In this booklet, the mathematical vocabulary printed in red, is new vocabulary and these words will be taught to your child for the first time. Words printed in black words are words that they will have met during an earlier stage. The following pages will guide you through how we teach calculations at All Saints Infant School and this booklet will be supported through parent workshops. Please look out for dates on class notice boards, newsletters, on our website and in book bags. If you have any questions, please approach your child s class teacher who will be happy to go through the calculations with you.

3 Addition Stage 2 Manipulatives Straws, Numicon, Dienes, Number lines, Bead Strings, 100 squares Language addition, more, plus, and, make, altogether, total, double, near double, equals most, count on and number line, number bonds/pairs/facts, is the same as, missing number, tens boundary, tens, units, column one more, two more ten more one hundred more How many more to make? How many more is than? How much more is?

4 Add 2-digit numbers Developing mental fluency with addition and place value involving 2-digit number, then establish more formal written methods. To support understanding, pupils may physically make and carry out the calculation with Dienes base 10 apparatus and compare their practical version to the written form, to help them build an understanding of it. Key skills for addition at Stage 2 Add a 2-digit number and ones (e.g 27+6) Add a 2-digit number and tens (e.g ) Add pairs of 2-digit numbers (e.g ) Add three single digit numbers (e.g 5+9+7) Show that adding can be done in any order Recall bonds to 20 and bonds of 10s to 100 (e.g etc) Count in steps of 2, 3 and 5 and count in 10s from any number Understand the place value of 2 digit numbers (tens and ones) Compare and order numbers to 100 using < > Read and write numbers to at least 100 in numerals and words

5 Solve problems with addition, using concrete objects, pictorial representations, involving numbers, quantities and measures and applying mental and written methods Subtraction Stage 2 Manipulatives Number lines, bead strings, Dienes, straws, hundred squares, place value grids Language take away, difference between How many are left/left over? How many have gone? One less, two less, ten less 100 less How many fewer is than? How much less is? Half, halve, subtract, equals, is the same as, missing number, number bonds/pairs/facts, tens boundary, minus, leaves, count back, partition, tens, units Subtract with 2-digit numbers Subtract using Dienes on a grid Tens Units

6 Learn to exchange one ten for 10 units Tens Units Subtract on a number line by counting back, aiming to develop mental subtraction skills. This strategy will be used for: 2-digit numbers subtract units (by taking away/counting back) e.g digit numbers subtract tens (by taking away/counting back) e.g Subtracting pairs of 2-digit numbers (see below) Mental strategy subtract numbers close together by counting on: Start with the smaller number and count on to Many mental methods are taught, children are taught to recognise that when numbers are close together, it is more efficient to count on the difference. They need to be clear of the relationship between addition and subtraction.

7 Key skills for subtraction in Stage 2 Recognise the place value of each digit in a two-digit number Recall and use subtraction facts to 20 fluently, and derive and use related facts up to 100 Subtract using concrete objects, pictorial representations, 100 squares and mentally, including: a two-digit number and ones, a two-digit number and tens and two two-digit numbers. Show that subtraction from one number to another cannot be done in any order Recognise and use inverse relationships between addition and subtraction, using this to double check calculations and missing number problems Solve simple addition and subtraction problems including measures Read and write number to at least 100 in numerals and words. Multiplication Stage 2 Manipulatives Concrete objects, bead strings, number lines Language Counting in 2s, same, doubling, equally, how many? number patterns, groups, multiplication, multiply, multiplied by, multiple, grouping, array, groups of, times, once, twice, three times.ten times, repeated addition, one each, two each, three each ten each, row, column, multiplication table, multiplication fact. Multiply using arrays and repeated addition (using at least 2s, 5s and 10s) Use of fingers:

8 Use repeated addition on a number line: Start from zero, make equal jumps up on a number line to work out multiplication facts and write multiplication statements using x and = signs. Use arrays: 3x5 =15 5x3= = 15 3x5 = = 15 5x3 =15 Use arrays to help teach children to understand the commutative law of multiplication, and give children examples such as 3 x = 6. Use practical apparatus: The commutativity of multiplication Arrays help children understand the commutative law 2 x 5 = 5 x 2.

9 The Key skills for multiplication at Stage 2 Count in steps of 2, 3 and 5 from zero, and in 10s from any number Recall and use multiplication facts from the 2, 5 and 10 multiplication tables, including recognising odds and evens. Write and calculate number sentences using the x and = signs Show that multiplication can be done in any order (commutative) Solve a range of problems involving multiplication, using concrete objects, arrays, repeated addition, mental methods and multiplication facts Pupils use a variety of language to discuss and describe multiplication Division Stage 2 Manipulatives Bead strings, Concrete objects, Number lines, arrays, Dienes Language Sharing, halving, number patterns, division, dividing, grouping, array, groups of, equal groups of, divide, divided by, divided into, share equally, left, left over, one each, two each, three each ten each, group in pairs, threes tens, division fact Group and share, using the and = signs Use objects, arrays, diagrams and pictorial representations and grouping on a number line. Arrays Children understand the commutative law does not work for division but understand how division relates to multiplication This represents how many groups of 3 in 12? 12 4 = 3

10 Key skills for division at Stage 2 Count in steps of 2,3 and 5 from 0 Recall and use multiplication and division facts for the 2,5 and 10 multiplication tables, including odd and even numbers Calculate mathematical statements for multiplication and division within the multiplication tables and write them using x, and = signs Show that multiplication can be done in any order but division cannot Solve problems involving multiplication and division, using materials, arrays, repeated addition, metal methods and multiplication and division facts, including problems in context.