The school distributes 60% of the purchased books to the fourth, fifth and sixth grades according to the ratio of 2:3:4. It is known that the sixth grade is allocated 56 books, how many books have the school purchased in total?
学校把购进的图书的60%按2：3：4分配给四、五、六三个年级．已知六年级分得56本，学校共购进图书多少本？
<gadget id="calculator">2 + 3 + 4</gadget>
<output>9</output>

<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">56 / (4/9) / (3/5)</gadget>
<output>210</output>

<result>210</result>