Used BC Math Functions

Author: ojhaujjwal

src/Crisu83/Conversion/Quantity/Quantity.php

@@ -63,7 +63,7 @@ public function add($quantity, $unit = null)
         /** @var Quantity $quantity */
         $quantity = new static($quantity, $unit);
         $quantity->to($this->unit);
-        $this->value += $quantity->getValue();
+        $this->value = bcadd($this->value, $quantity->getValue());
         return $this;
     }
 
@@ -81,7 +81,7 @@ public function sub($quantity, $unit = null)
         /** @var Quantity $quantity */
         $quantity = new static($quantity, $unit);
         $quantity->to($this->unit);
-        $this->value -= $quantity->getValue();
+        $this->value = bcsub($this->value, $quantity->getValue());
         return $this;
     }
 
@@ -106,7 +106,7 @@ public function to($unit)
      */
     protected function convert($from, $to, $value)
     {
-        return ($value * $this->getConversionRate($from)) / $this->getConversionRate($to);
+        return bcdiv(bcmul($value, $this->getConversionRate($from)), $this->getConversionRate($to));
     }
 
     /**