Xiao Ming read 90 pages today, more than yesterday (1/9). Question: How many pages did Xiao Ming read yesterday?
小明今天看书90页，比昨天多(1/9)．问：小明昨天看书多少页？
<gadget id="calculator">1 / 9</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">1 + (1/9)</gadget>
<output>10/9 = around 1.111111</output>

<gadget id="calculator">90 / (10/9)</gadget>
<output>81</output>

<result>81</result>