piece of rectangular paper is 42cm long and 28cm wide. If you cut it into many squares, there should be no leftovers. How many squares can you cut at least?
一张长方形纸长42cm，宽28cm，把它切割成许多正方形，不能有剩余，最少可以割成几张正方形呢？
<gadget id="calculator">2 * 7</gadget>
<output>14</output>

<gadget id="calculator">42 / 14</gadget>
<output>3</output>

<gadget id="calculator">28 / 14</gadget>
<output>2</output>

<gadget id="calculator">3 * 2</gadget>
<output>6</output>

<result>6</result>