Year 3 Block A: - Suffolk Learning

10 of 20 The National Strategies ⏐ PrimaryYear 3 Block A: Counting, partitioning and calculatingAssessment focus: Ma2, Numbers and the number systemLook for evidence of children’s understanding of place value. Look for children who know whichdigit will change when they add or subtract 10 or 100. Look for evidence of children who canmultiply whole numbers by 10 and divide numbers by 10 where the answer is a whole number.Look for children who map a set of numbers onto numbers in a corresponding set, using therelationship ‘× 10 =’ or ‘÷ 10 =’. Look out for children who begin to use this with amounts ofmoney, for example, children who recognise that 45p maps onto £4.50, using the relationship‘× 10 = ’.Children partition two-digit numbers in different ways; for example, they recognise that 75 canbe partitioned into 70 + 5 or 60 + 15. They use partitioning flexibly to support calculationstrategies, for example, partitioning 75 into 60 + 15 in order to subtract 28 by subtracting 20 from60 and 8 from 15. They solve problems involving partitioning, such as:If two people share £38 and one person gets £10 more than the other, how much do theyeach get?They use diagrams to help them solve these problems and record their solutions.Children understand the term difference. They appreciate that Find the difference between 38and 52 is equivalent to the question: How much greater is 52 than 38? and relate these to thesubtraction 52 – 38. They find the difference by counting up from 38 to 52. Children usepartitioning to add or subtract mentally one- and two-digit numbers. For example, they calculate37 + 26 by using 37 + 20 + 6 and 37 – 26 by working out 37 – 20 – 6, recording the steps on anumber line. Children begin to check their addition and subtraction with a calculation that usesthe inverse operation. They know that subtracting 18 from 34 to get 16 can be checked byadding 18 to 16.Assessment focus: Ma2, Operations and relationships between themLook for evidence of children using inverse operations. Look for children who find missingnumbers in examples such as 36 + = 56. Look for children who, given three numbers such as14, 24 and 10, create a set of related addition and subtraction sentences or, given 14, 10 and140, create a set of related multiplications and divisions. Look for children who solve problemssuch as: ‘I think of a number, double it and add 5. The answer is 47. What number did I thinkof?’ Look out for children who are beginning to understand the role of the equals sign, ‘=’, innumber sentences with missing numbers, such as 6 × 10 = 75 – .Children solve puzzles and problems that involve all four operations. They use theirknowledge of multiplication and division to find the cost of boxes of six items where each itemcosts 40p or the number of boxes of four items that can be filled from 30 items. They developstrategies to solve ‘think of a number’ problems that involve halving and doubling. They explorenumbers, looking for pairs that total 30 and have a difference of 12, by listing possible pairs andtesting to see if the second criterion holds. Children discuss and explain their methods orallyand begin to record, using pictures or diagrams. They follow the explanations of others, forexample, how they solved 'think of a number' problems. They compare different approaches andsuggest possible modifications.00543-2008DOM-EN-11 © Crown copyright 2009