Uncle Li used a 9.7-meter-long bamboo pole to measure the water depth of the pool. After the bamboo pole was inserted into the bottom of the water, it was 1.8 meters above the water surface. How many meters is the water depth?
李叔叔用一根长9.7米的竹竿测量水池的水深，竹竿插入水底后，露出水面1.8米，水深多少米？
<gadget id="calculator">9.7 - 1.8</gadget>
<output>7.9</output>

<result>7.9</result>