STAGE 1 - Counting Back
STAGE 5 - Developing Formal Written Method
Count back using number tracks / number lines / 100 grids to support. Link
concept of number bonds to ten to subtraction facts.
Continue to determine when mental strategies are appropriate. When developing written method use practical apparatus to support formal written method,
using expanded recording as needed to support understanding. Recap without
exchange, then develop with exchange.
STAGE 2 - Introducing Partitioning and Place Value
Develop understanding of equality through empty box problems. Use language
of “difference”. Use understanding of patterning, place value and partitioning
to derive number facts. Begin to use understanding of place value and partitioning to carry out subtraction of one digit numbers from two digit numbers.
7 - 3 = 4 (known fact)
17 - 3 = 14
27 - 3 = 24
SUBTRACTION
CALCULATION SUMMARY
STAGE 3 - Developing Partitioning and Place Value
STAGE 6 - Extending Formal Written Method
Continue to use understanding of place value and partitioning to carry out
subtraction of one digit and two digit numbers, first supported by apparatus
and recorded horizontally, then recording in columns to focus on place value
still with the support of apparatus as needed. Developing efficient methods on
the empty number line is important for mental strategies later.
Continue to decide when calculations are best carried out using mental strategies. Extend the standard written method to introduce hundreds columns,
using expanded recording and apparatus initially if required to support understanding. Explore the process with zero place holders.
41 - 8
= 40 - 7
= 33
STAGE 4 - Introducing Formal Written Method
Pupils are encouraged to decide when calculations are best carried out using
mental strategies. Horizontal recording can begin to be replaced with recording in columns to focus on place value. Use expanded recording
and apparatus to develop concept before moving towards the formal
written method. Begin with no exchange, then move to exchanging.
STAGE 7 - Securing Formal Written Method
Continue to consider whether mental strategies or written methods
are most efficient for given calculations. Develop the use of formal
column addition to include increasingly large numbers and decimals. Use expanded recording and apparatus as necessary to support understanding.