Let a*b=3a-b*(1/2), find (25*12)*(10*5).
设a*b=3a-b*(1/2)，求(25*12)*(10*5)．
<gadget id="calculator">69 * 3</gadget>
<output>207</output>

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

<gadget id="calculator">27.5 * (1/2)</gadget>
<output>13.75</output>

<gadget id="calculator">207 - 13.75</gadget>
<output>193.25</output>

<result>193.25</result>