a and b are two different natural numbers less than 100, then the maximum value of ((2a-2b)/(a+b)) is (49/25). a and b are two different natural numbers less than 100, find the maximum value of (((ab))/((a+b))).
a和b是小于100的两个不同的自然数，则((2a-2b)/(a+b))的最大值是(49/25)．a和b是小于100的两个不同的自然数，求(((a-b))/((a+b)))的最大值．
<gadget id="calculator">99 - 1</gadget>
<output>98</output>

<gadget id="calculator">99 + 1</gadget>
<output>100</output>

<gadget id="calculator">98 / 100</gadget>
<output>49/50 = around 0.98</output>

<result>49/50 = around 0.98</result>