There is a pile of the same steel balls with a total mass of 900 grams. After taking out 32 balls, the remaining mass is 420 grams. How many steel balls are there in this pile?
有一堆同样的钢球，总质量为900克，取出32个后，剩下的质量为420克，这堆钢球一共有多少个？
<gadget id="calculator">900 - 420</gadget>
<output>480</output>

<gadget id="calculator">480 / 32</gadget>
<output>15</output>

<gadget id="calculator">900 / 15</gadget>
<output>60</output>

<result>60</result>