Master Liu wants to process a batch of parts, half of the total number has been processed, less than 3, and there are 45 parts left unprocessed, how many parts are there in this batch?
刘师傅要加工一批零件，已经加工了总数的一半少3个，还剩45个零件没有加工，则这批零件共有多少个．
<gadget id="calculator">45 - 3</gadget>
<output>42</output>

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

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

<gadget id="calculator">42 / (1/2)</gadget>
<output>84</output>

<result>84</result>