It takes (3/20) meters of steel to make a part A, and less steel (7/9) to make a part B than to make a part A. After making 4 parts A with a length of 1 meter, how many more can you make? A B part?
做一个甲零件需要钢材(3/20)米，做一个乙零件所需钢材比做一个甲零件少(7/9)，用一段长1米的钢材做4个甲零件后，还能做几个乙零件？
<gadget id="calculator">3 / 20</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">(3/20) * 4</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">7 / 9</gadget>
<output>7/9 = around 0.777778</output>

<gadget id="calculator">1 - (7/9)</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">(3/20) * (2/9)</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">(2/5) / (1/30)</gadget>
<output>12</output>

<result>12</result>