Xiaogang’s family used 90 degrees of electricity in June, which was 1/10 less than in May. How much electricity was used in May?
小刚家六月份用电90度，比五月份节约了(1/10)，五月用电多少度？
<gadget id="calculator">1 / 10</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">90 / (9/10)</gadget>
<output>100</output>

<result>100</result>