Grandpa Zhang inserted a 5-meter-long bamboo pole vertically into the pond. The part of the bamboo pole that enters the mud is 0.7 meters, and the part that is exposed to the water is 1.38 meters. How many meters is the water depth of this pond?
张爷爷把一根5米长的竹竿垂直插入池塘中，竹竿的入泥部分是0.7米，露出水面的部分是1.38米，这个池塘的水深是多少米？
<gadget id="calculator">5 - 0.7 - 1.38</gadget>
<output>2.92</output>

<result>2.92</result>