The number of popular science books in the school library plus 213, and then divided by 3, is the number of literature and art books. There are 668 literature and art books. How many popular science books are there in the library? (solution with equation)
学校图书馆里科普书的本数加上213本，再除以3，就是文艺书的本数，文艺书有668本，图书馆里有科普书多少本？(用方程解答)
<gadget id="calculator">213 / 3</gadget>
<output>71</output>

<gadget id="calculator">668 - 71</gadget>
<output>597</output>

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

<gadget id="calculator">597 / (1/3)</gadget>
<output>1_791</output>

<result>1_791</result>