A piece of alloy contains copper and zinc in a ratio of 3:4. Use this alloy to manufacture 63 grams of a new alloy with a copper-zinc ratio of 1:2. Ask whether to add copper or zinc, and how many grams to add.
一块合金含铜与锌比为3：4，用此合金制造铜锌之比为1：2的新合金63克，问要加铜还是加锌，加多少克．
<gadget id="calculator">1 + 2</gadget>
<output>3</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">63 * (2/3)</gadget>
<output>42</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(1/3) / 3</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">63 * (1/9) * 4</gadget>
<output>28</output>

<gadget id="calculator">42 - 28</gadget>
<output>14</output>

<result>14</result>