12 students from Class 4, Class 1 of Experimental Primary School participated in the tree planting activity. Among them, the boys planted 5 trees each, and the girls planted 4 trees each. A total of 56 trees were planted. How many boys are there?
实验小学四1班12名学生参加植树活动，其中男生每人植树5棵，女生每人植株4棵，一共植树56棵，男生有多少人
<gadget id="calculator">12 * 5</gadget>
<output>60</output>

<gadget id="calculator">60 - 56</gadget>
<output>4</output>

<gadget id="calculator">5 - 4</gadget>
<output>1</output>

<gadget id="calculator">4 / 1</gadget>
<output>4</output>

<gadget id="calculator">12 - 4</gadget>
<output>8</output>

<result>8</result>