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Progression in Subtraction. Areas Addressed. Partitioning Discussing subtraction strategies Developing Column Subtraction Column Subtraction. Progression in Subtraction. Subtraction Lower Key Stage 2 Partitioning. Partitioning in different ways.
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Areas Addressed • Partitioning • Discussing subtraction strategies • Developing Column Subtraction • Column Subtraction
Progression in Subtraction Subtraction Lower Key Stage 2 Partitioning
Partitioning in different ways • Numbers can be partitioned in different ways, but in this lesson the teacher highlights partitioning into hundreds, tens and ones. • How might this be helpful for children moving towards a column method?
Pattern • Notice how Julie encourages the spotting of patterns and working systematically 143 100 + 40 + 3 100 + 30 + 13 100 + 20 + 23 100 + 10 + 33 143 100 + 40 + 3 90 + 50 + 3 80 + 60 + 3 60 + 80 + 3
Progression in Subtraction Subtraction Lower Key Stage 2 Discussing subtraction strategies
Arithmetic proficiency • The teacher is encouraging children to think about different strategies for subtraction. • How might this support the development of fluency in both mental and written calculation?
Language • Children are able to name the strategies they are using, for example: Adjusting Partitioning • Consider the use and development of mathematical language and how this might support fluency in calculation.
Progression in Subtraction Subtraction Lower Key Stage 2 Developing column subtraction Kibworth Video 1.3
Re-partitioning and exchange • One hundred and fifty and two is the same as one hundred and forty and twelve. • How does the use of place value counters support children’s understanding of this important idea?
Progression in Subtraction Subtraction Upper Key Stage 2 Column subtraction
Fluency and Efficiency • Consider when the traditional algorithm • might be the most efficient method? • Mental methods can sometimes be more • efficient even when the numbers are large. • Provide some examples
Place value counters • Notice how the place value counters support the concept of exchange. • Notice how the use of the counters helps the children express a quantity value understanding of fifty being equivalent to five tens.
What’s the same?What’s different? • Consider how the use of these questions supported opportunities for children to transfer their conceptual understanding and explain their mathematical reasoning. • Consider the vocabulary and language the children use.
765 - 348 60 5 300 40 8 7 6 5 3 4 8
The inverse operation • Notice how the children are able to use an inverse operation to check the answer to their calculations.
Important elements and next steps • What elements does the teacher identify for successful movement to a compact written method? • What does she identify as the next steps in children’s learning?