A, B, C and D went to water the trees, A watered the other three (1/2), B watered the other three (1/3), C watered the other three (1/4), D watered 13 trees ． How many trees did they water in total?
甲乙丙丁去浇树，甲浇了其他三人的(1/2)，乙浇了其他三人的(1/3)，丙浇了其他三人的(1/4)，丁浇了13棵．他们一共浇了多少棵？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/3) - (1/4) - (1/5)</gadget>
<output>13/60 = around 0.216667</output>

<gadget id="calculator">13 / (13/60)</gadget>
<output>60</output>

<result>60</result>