There are (9/2) tons of yellow sand on the construction site, (1/2) tons were used in the first week, and the remaining (1/2) was used in the second week, how many tons were used in the second week?
工地上有黄沙(9/2)吨，第一周用去(1/2)吨，第二周用去了剩下的(1/2)，第二周用去了多少吨？
<gadget id="calculator">9 / 2</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(9/2) - (1/2)</gadget>
<output>4</output>

<gadget id="calculator">4 * (1/2)</gadget>
<output>2</output>

<result>2</result>