The two most powerful numeracy concepts in Primary School are the number line and measurement. From there, you can use these in a variety of different domains. The number line, for instance, can instantly become useful when doing timelines of historical events. The number line theory is also easy to differentiate students by asking them to find quantities of time between events. Measurement allows student to get a concrete grasp of the world by being able to quantify the things they see around them – the food they eat, the water they pour, the temperature that’s raised. This can be useful in sciences or health studies as well, or ongoing statistical analysis projects. These two ideas make cross curriculum design much easier.