When Lele was doing an addition calculation, he regarded the 2 on the tens digit as 5, and the resulting sum was 89. What is the correct sum?
乐乐在做一道加法算式时，把一个加数十位上的2看成了5，结果得到的和是89，正确的和是多少
<gadget id="calculator">50 - 20</gadget>
<output>30</output>

<gadget id="calculator">89 - 30</gadget>
<output>59</output>

<result>59</result>