There are two bags of sugar, one with 84 grains and one with 20 grains. Each time, take out 8 grains from the more bag and put them into the less bag. After how many times, can the number of sugar grains in the two bags be the same?
有两袋糖，一袋是84粒，一袋是20粒．每次从多的一袋里取出8粒放到少的一袋里，经过几次，能使两袋糖的粒数相同？
<gadget id="calculator">84 - 20</gadget>
<output>64</output>

<gadget id="calculator">8 + 8</gadget>
<output>16</output>

<gadget id="calculator">64 / 16</gadget>
<output>4</output>

<result>4</result>