In the "Love and Book Donation" activity held by the school, the sixth grade students donated 150 books, and the number of books donated by the fifth grade students was 20% less than that of the sixth grade students. How many books did the fifth grade donate?
在学校举行的"献爱心捐图书"的活动中，六年级同学捐了150本图书，五年级同学捐的本数比六年级少20%．五年级捐了多少本图书？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">150 * (4/5)</gadget>
<output>120</output>

<result>120</result>