Boss Zhang bought 624 sets of learning tools for 1,872 yuan. He sold 389 sets at a price of 4 yuan each, and the remaining sets were sold at 3 yuan each. How much did he earn in total?
张老板花了1872元钱买了624套学习用具，他以每套4元的价格卖出了389套，剩余的每套卖3元，请问他一共赚了多少钱？
<gadget id="calculator">4 * 389</gadget>
<output>1_556</output>

<gadget id="calculator">624 - 389</gadget>
<output>235</output>

<gadget id="calculator">3 * 235</gadget>
<output>705</output>

<gadget id="calculator">705 - 1_872</gadget>
<output>-1_167</output>

<gadget id="calculator">1_556 + (-1_167)</gadget>
<output>389</output>

<result>389</result>