The store originally had 120 kilograms of apples, and 10 boxes of apples were shipped in, each weighing a kilogram. Use the formula to express the total mass of apples in this store in kilograms.
商店原来有120千克苹果，又运来10箱苹果，每箱重a千克．用式子表示出这个商店里苹果的总质量多少千克．
<gadget id="calculator">120 + 10</gadget>
<output>130</output>

<result>130</result>