title: Binary operator '-' cannot be applied to two 'CGFloat' operands
body: <p>I'm writing 3D game and trying to write expression in the handler of the extracted taps:</p>
  
  <pre><code>  override func touchesMoved(_ touches: Set&lt;UITouch&gt;, with event: UIEvent!) {
  
      for touch: AnyObject in touches {
          let touchPoint: CGPoint  = touch.location(in: self)
  
           if (isTracking == true &amp;&amp; sqrtf(powf((touchPoint.x - thumbNode.position.x), 2) + powf((touchPoint.y - thumbNode.position.y), 2)) &lt; size * 2)
          {...}
       }
    }
  </code></pre>
  
  <p>But Xcode wrote error:</p>
  
  <p><strong>Binary operator '-' cannot be applied to two 'CGFloat' operands.</strong></p>
  
  <p>Than tried:</p>
  
  <pre><code> var arg_3 = (touchPoint.x - self.anchorPointInPoints().x)
   var expr_3 = powf(Float(arg_3), 2)
   var arg_4 = (touchPoint.y - self.anchorPointInPoints().y)
   var expr_4 = powf(Float(arg_4),2)
   var expr_5 = expr_3 + expr_4
   var expr_6 = thumbNode.size.width
  
   if (sqrtf(Float(expr_5)) &lt;= expr_6)
   {}
  </code></pre>
  
  <p>Now it wrotes: </p>
  
  <p><strong>Binary operator '&lt;=' cannot be applied to operands of type 'Float' and 'CGFloat'</strong></p>
  
  <p>Please help me to fix that problem.</p>
  
  <p>Thanks in advance.</p>