When Li Ming calculates 15+(1/3)*□, he calculates 15+(1/3) first by mistake, and the calculated result is 3 less than the correct result. What is the number in □?
李明在计算15+(1/3)*□时，错误地先算15+(1/3)，这样算出的结果比正确的结果少3．□中的数是多少？
<gadget id="calculator">15 - 3</gadget>
<output>12</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(1/3) - (1/3)</gadget>
<output>0</output>

<gadget id="calculator">15 + 0</gadget>
<output>15</output>

<gadget id="calculator">12 / 15</gadget>
<output>4/5 = around 0.8</output>

<result>4/5 = around 0.8</result>