Serious soil erosion has caused about 1.6 billion tons of sediment to flow into the Yellow River every year. Wherein (1/4) the silt is deposited in the river course, and the rest is taken to the estuary, how many billion tons of silt is brought to the estuary?
严重的水土流失致使每年大约有16亿吨的泥沙流人黄河．其中(1/4)的泥沙沉积在河道中，其余被带到入海口，有多少亿吨泥沙被带到入海口？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">16 * (1/4)</gadget>
<output>4</output>

<gadget id="calculator">16 - 4</gadget>
<output>12</output>

<result>12</result>