Teacher Li received a batch of exercise books from the school and distributed them to 38 students in the class. Each person was divided into 4 books. When the last person was assigned, he found that there was a difference of 1 book. How many books are there in this batch of exercise books?
李老师从学校领了一批练习本，分给班上的38位同学，每人分4本，分到最后一个人时，发现差1本，这批练习本一共有多少本？
<gadget id="calculator">38 * 4</gadget>
<output>152</output>

<gadget id="calculator">152 - 1</gadget>
<output>151</output>

<result>151</result>