A fraction reduced to the simplest fraction is (2/3), the sum of the numerator and denominator of the original fraction is 90, what is the original fraction?
一个分数约成最简分数是(2/3)，原分数分子与分母之和是90，原分数是多少？
<gadget id="calculator">3 + 2</gadget>
<output>5</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

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

<gadget id="calculator">90 * (3/5)</gadget>
<output>54</output>

<gadget id="calculator">(2/5) / 54</gadget>
<output>1/135 = around 0.007407</output>

<gadget id="calculator">90 * (1/135)</gadget>
<output>2/3 = around 0.666667</output>

<result>2/3 = around 0.666667</result>