Year Three use a number line to count on when adding single digits, building on the method taught in the previous year. They also begin to partition numbers, with the help of manipulatives, so they can bridge to ten when crossing ten. They then transfer this knowledge to column method with renaming and are introduced to the bar model.
In Year Four, the column method is extended further, adding numbers with 4 digits. They use it both with and without renaming. They develop the bar model further as a way of helping them see what calculation is needed. Finally, they begin to manipulate numbers to make more complicated calculations simpler.
Year Five continue manipulating numbers by looking at ways to add multiples of 1000 by dividing both numbers by 1000, adding them, then multiplying the answer by 1000. They also use their previous knowledge of place value to understand that when adding multiples of ten/hundred/thousands, only the ten/hundreds/thousands need to considered.
When in Year Six, the children consolidate their addition methods and are encouraged to look for the most efficient method for the calculation. They continue to use the column method but also apply it to adding decimal numbers. With a secure understanding of column method, the children are able to use it to solve missing number problems.