There are 30 steel balls of the same type in a wooden box, and the weight of the box is 330 grams. After taking out 10 steel balls, the weight of the box is 270 grams. How many grams does each steel ball weigh?
一个木盒里装有30颗同种型号的钢珠，连盒重330克．取出10颗钢珠后，连盒重270克．每颗钢珠重多少克？
<gadget id="calculator">330 - 270</gadget>
<output>60</output>

<gadget id="calculator">60 / 10</gadget>
<output>6</output>

<result>6</result>