The school bought a total of 80 science and art books, of which the number of literature and art books is the number of science and technology books (7/9), how many science and technology books are there? (column equation solution)
学校买来科技书、文艺书共80本，其中文艺书的本数是科技书的(7/9)，科技书有多少本？(列方程解答)
<gadget id="calculator">7 / 9</gadget>
<output>7/9 = around 0.777778</output>

<gadget id="calculator">1 + (7/9)</gadget>
<output>16/9 = around 1.777778</output>

<gadget id="calculator">80 / (16/9)</gadget>
<output>45</output>

<result>45</result>