Once ‘teen’ and ‘ty’ numbers have both been introduced, it can be beneficial to use targeted diagnostic sheets to identify any confusion and provide correct reinforcement.

‘Teen’ and ‘ty’ confusion may not always be obvious. It is important to be aware that a child who struggles with ‘teen’ and ‘ty’ numbers may be able to read and write these numbers correctly when asked to do so. However, when combined with other activities, such as counting forwards or backwards, or answering simple addition/subtraction calculations, mistakes may arise. Seemingly random incorrect answers to questions involving such numbers may be due to an underlying confusion which needs addressing.