Dahua Machine Tool Factory now produces 6 more machine tools per month than three times the previous monthly production. Now the monthly output is 321 units, how many units were produced per month in the past?
大华机床厂现在每月生产机床的产量比过去每月产量的3倍多6台．现在每月的产量是321台，过去每月生产多少台？
<gadget id="calculator">321 - 6</gadget>
<output>315</output>

<gadget id="calculator">315 / 3</gadget>
<output>105</output>

<result>105</result>