A batch of water heaters was sold in a shopping mall, half of which were sold and 3 units were left, and there were 25 left. How many water heaters were there in this batch?
商场销售一批热水器，已经卖了一半少3台，还剩下25台，这批热水器原来有多少台？
<gadget id="calculator">25 - 3</gadget>
<output>22</output>

<gadget id="calculator">22 * 2</gadget>
<output>44</output>

<result>44</result>