Little carelessness, too careless, misreading the question when calculating subtraction, copying the 8 of the subtrahend into 3, and copying the 2 of the tens digit into 5, so the calculated difference is 305. Do you know what the correct number is?
小粗心，太大意，计算减法看错题，被减数个位的8抄成3，减数十位的2抄成5，这样算出的差是305．你知道正确得数是几吗？
<gadget id="calculator">50 - 20</gadget>
<output>30</output>

<gadget id="calculator">8 - 3</gadget>
<output>5</output>

<gadget id="calculator">305 + 30 + 5</gadget>
<output>340</output>

<result>340</result>