After the earthquake in Wenchuan County, Nanguan Primary School held a book donation activity of "connecting hearts and hands". The fifth grade donated a total of 117 books, 10% less than the sixth grade. How many books did the sixth grade donate? (solution by equation)
汶川县大地震之后，南关小学举行了"心手相连"的捐书活动．五年级共捐了117本书，比六年级少捐10%，六年级捐了多少本书？(用方程解)
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 - (1/10)</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">117 / (9/10)</gadget>
<output>130</output>

<result>130</result>