Ten people from a tree-planting team of a primary school in Taihe Town participated in the tree-planting activity. Each of the boys planted 5 trees, and each of the girls planted 3 trees, a total of 42 trees were planted. How many boys are there?
太和镇某小学植树小分队10人参加植树活动．男生每人栽了5棵树，女生每人栽了3棵树，一共栽了42棵树．男生有多少人．
<gadget id="calculator">10 * 5</gadget>
<output>50</output>

<gadget id="calculator">50 - 42</gadget>
<output>8</output>

<gadget id="calculator">5 - 3</gadget>
<output>2</output>

<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">10 - 4</gadget>
<output>6</output>

<result>6</result>