Subtract the same number from the numerator and denominator of (49/79) to get (2/7).
从(49/79)的分子与分母里，减去相同的数多少，就成为(2/7)．
<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">(2/7) * 79</gadget>
<output>158/7 = around 22.571429</output>

<gadget id="calculator">49 - (158/7)</gadget>
<output>185/7 = around 26.428571</output>

<gadget id="calculator">1 - (2/7)</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">(185/7) / (5/7)</gadget>
<output>37</output>

<result>37</result>