Many schools have a whole school Numeracy policy, I have looked through a lot and there are some great examples on the Suffolk Maths website. 

Having talked to staff across different subject areas at my school, I was keen to develop a policy that reflected what they wanted to see in terms of developing Numeracy across the curriculum. What emerged from a series of meetings we held after school was that we wanted a policy that:

1) Supported better consistency in the teaching of Mathematics / Numeracy across the curriculum

2) Gave examples of how Mathematics / Numeracy is used in practice across the curriculum

3) Supported better collaboration between different subject areas

The policy I developed alongside staff from other departments (Science, Geography, History, English, PE, DT to name a few) provides many of the usual elements of a Numeracy policy (vision, Mathematical methods, how parents can support their children at home) but also gives cross curricular examples from different subject areas.

The idea is that it is a working document and it is designed to be accessed online, although people could get a printed copy if they wanted one. It may seem quite lengthy and may not suit all schools but it covers what the staff at my school wanted to see included and will be the basis of collaboration between departments and CPD sessions in the next academic year. 

You can access a copy of the policy here.