How to add numbers from cells?

Question

CodeIgniter

How to count numbers from amount in cms_operations table?
and display in the
Model view

function getBalanceByID()
    {
    $this->db->select_sum('amount');
    $query = $this->db->get('cms_operations');
    return $query->result();
    }

Controller

public function index()
  {
    $this->load->view('v_header');
    
    $this->load->model('mdl_billing');
    $data['query'] = $this->mdl_billing->getBalanceByID();
    $this->load->view('v_billing', $data);
  
    $this->load->view('v_billing');
    $this->load->view('v_footer');
  }

view
????