matchbox is 4 cm long, 2.5 cm wide, and 1 cm high, what is the sum of its sides in cm?
一个火柴盒长4厘米，宽2.5厘米，高1厘米，它的棱长总和是多少厘米．
<gadget id="calculator">4 + 2.5 + 1</gadget>
<output>7.5</output>

<gadget id="calculator">7.5 * 4</gadget>
<output>30</output>

<result>30</result>