Have you checked the ORM API documentation (https://www.odoo.com/documentation/9.0/reference/orm.html#computed-fields)?

Are you going to add an additional field to the model? If so something like the following should work.

x_uvp_display = fields.Float(string='UVP scaled'. compute='_compute_x_uvp_display')

@api.onchange('x_uvp')
@api.depends('x_uvp')
def _compute_x_uvp_display(self):
     for rec in self:
         rec.x_uvp_display = rec.x_uvp / 1.19