If it takes 1 hour to saw a piece of wood into 3 pieces, how many minutes will it take to saw the piece of wood into 4 pieces?
把一根木头锯成3段需1小时，把这根木头锯成4段需多少分钟．
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">60 / 2</gadget>
<output>30</output>

<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">30 * 3</gadget>
<output>90</output>

<result>90</result>