Value round and fetch data through slug or name

 {{round($per,2)}}

  $details = Product::where('product_slug', $product_slug)->firstorfail();

        $save = $details->product_compare_price - $details->product_original_price;

        $per=($save*100)/$details->product_compare_price;

        round($per, 2);

        // echo "<pre>";

        // dd($per);

        $similar_product=Product::all();

        $data = compact('details', 'save','similar_product','per');

        // echo "<pre>";

        // print_r($similar_product);

        return view('front.Details.details')->with($data);