The expanded method of addition is usually introduced in Lower Key stage 2 but each teacher will place a different emphasis on this stage of the learning, depending on pupils' progress. School evidence suggests that as a precursor to the more efficient column methods, it is a crucial stage of the learning. It serves to guide children towards columnar value concepts in preparation for more difficult algorithms, especially where numerals start to cross the boundaries of powers of ten and 'exchanging' is required. Whilst expanded methods of addition will naturally identify more able students who are ready to move on to column methods, most teachers would agree that for a few children, confusion is most likely to occur during this stage of the learning. Haylock (2010) and Hansen (2011) endorse the idea that children who are identified as being less confident should receive more practical intervention within the learning, whilst evidence across schools has demonstrated how visual and manipulative resources will positively support accurate written methods; helping to prevent "cognitive overload" in the calculation process which is often the issue (Ryan and Williams 2007:13). Moreover, working with base ten blocks and place value grids will enable easier transition towards 'exchanging'.