Uncle Li bought back 6 bags of flour, each weighing 25 kilograms; 4 bags of rice, each weighing 30 kilograms. How many kilograms less rice is bought than flour?
李大爷买回面粉6袋，每袋重25千克；大米4袋，每袋30千克．买回的大米比面粉少多少千克？
<gadget id="calculator">25 * 6</gadget>
<output>150</output>

<gadget id="calculator">30 * 4</gadget>
<output>120</output>

<gadget id="calculator">150 - 120</gadget>
<output>30</output>

<result>30</result>