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. Do you want to add copper or zinc? How many grams should you 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">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">3 + 4</gadget>
<output>7</output>

<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">(1/3) / (3/7)</gadget>
<output>7/9 = around 0.777778</output>

<gadget id="calculator">63 * (7/9)</gadget>
<output>49</output>

<gadget id="calculator">63 - 49</gadget>
<output>14</output>

<result>14</result>