The fourth, fifth, and sixth grade students of Xincheng Primary School donated 1,013 books to poor students in mountainous areas, of which the fifth and sixth grade students donated 487 books and 313 books respectively. How many books do fourth graders donate? (The laws of operation can be used in the calculation process)
新城小学四、五、六年级学生为山区贫困学生捐赠图书1013本，其中五、六年级学生分别捐赠图书487本和313本．四年级学生捐赠图书多少本？(在计算过程中可以使用运算定律)
<gadget id="calculator">487 + 313</gadget>
<output>800</output>

<gadget id="calculator">1_013 - 800</gadget>
<output>213</output>

<result>213</result>