Three wooden sticks A, B, and C are inserted into the same pool. The sum of the lengths of the three wooden sticks is 270 cm. A has (3/4) outside the water surface, B has (7/10) outside the water surface, and C has (2/2) /5) How deep is the water outside the water surface?
甲、乙、丙三根木棒插入同一个水池中，三根木棒的长度和为270厘米，甲有(3/4)在水面外，乙有(7/10)在水面外，丙有(2/5)在水面外，求水有多深？
<gadget id="calculator">12 + 10 + 5</gadget>
<output>27</output>

<gadget id="calculator">12 / 27</gadget>
<output>4/9 = around 0.444444</output>

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

<gadget id="calculator">270 * (4/9) * (1/4)</gadget>
<output>30</output>

<result>30</result>