A road is divided equally between two engineering teams, A and B, for construction. The ratio of what Team A has repaired to what is left is 2:1, and the ratio of what Team B has repaired to what is left is 5:2. What fraction of the total length of this road has been built?
将一条公路平均分给甲、乙两个工程队修筑．甲队已修的与剩下的比是2：1，乙队已修的与剩下的比是5：2．这条公路已修了全长的几分之几？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 + 2</gadget>
<output>3</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(1/2) * (2/3)</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">5 + 2</gadget>
<output>7</output>

<gadget id="calculator">5 / 7</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">(1/2) * (5/7)</gadget>
<output>5/14 = around 0.357143</output>

<gadget id="calculator">(1/3) + (5/14)</gadget>
<output>29/42 = around 0.690476</output>

<result>29/42 = around 0.690476</result>