If it takes 15 minutes to saw a stick into 4 pieces, how many minutes will it take to saw it into 8 pieces?
把一根木棒锯成4段要15分钟，若锯成8段需要多少分钟．
<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">15 / 3</gadget>
<output>5</output>

<gadget id="calculator">8 - 1</gadget>
<output>7</output>

<gadget id="calculator">5 * 7</gadget>
<output>35</output>

<result>35</result>