Hope Primary School originally planned to buy 12 balls at 8.4 yuan each, but now they took 16.8 yuan out of the ball purchase money to buy a skipping rope. How many balls can the remaining money buy?
希望小学原计划买12个皮球，每个8.4元，现在从买皮球的钱中拿出16.8元买了跳绳，剩下的钱可买几个皮球？
<gadget id="calculator">16.8 / 8.4</gadget>
<output>2</output>

<gadget id="calculator">12 - 2</gadget>
<output>10</output>

<result>10</result>