The water in the human body accounts for about 7/10 of the body weight. Dong Dong's weight is 40 kg. How many kg of water does his body contain?
人体内的水大约占体重的(7/10)，冬冬的体重是40千克，他体内大约含水多少千克？
<gadget id="calculator">7 / 10</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">40 * (7/10)</gadget>
<output>28</output>

<result>28</result>