These workshops and accompanying resources are intended to support teachers in developing mental maths strategies in their classrooms. The Mental Maths Handbooks explore the key properties of number and number relationships, outlining practical approaches to developing an understanding of these. It also explores background knowledge for teachers and fundamental facts in relation to mental maths. A range of concrete, practical activities that will support pupils in their development of addition and subtraction mental maths strategies are also outlined. Finally, a selection of engaging and enjoyable activities to consolidate learning and provide opportunities for pupils to master addition and subtraction facts are included.