If the length of a rectangle is (4/15) cm and the width is (1/12) cm, what is its perimeter?
一个长方形的长是(4/15)cm，宽是(1/12)cm，那么它的周长是多少．
<gadget id="calculator">4 / 15</gadget>
<output>4/15 = around 0.266667</output>

<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(4/15) + (1/12)</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">(7/20) * 2</gadget>
<output>7/10 = around 0.7</output>

<result>7/10 = around 0.7</result>