The two outer terms are 1.25 and 1.6, and the two inner terms are 0.25 and X.
两个外项是1.25和1.6，两个内项是0.25和X．
<gadget id="calculator">1.25 / 0.25</gadget>
<output>5</output>

<gadget id="calculator">5 * 1.6</gadget>
<output>8</output>

<result>8</result>