There are 40 people in the school calligraphy interest group, of which boys accounted for (1/2), how many boys were added later, at this time boys accounted for the total number (5/9), how many boys came later?
学校书法兴趣小组有40人，其中男生占(1/2)，后来又加入几名男生，这时男生占总人数的(5/9)，后来又来了几名男生？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 - (1/2)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">1 - (5/9)</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">(1/2) / (4/9)</gadget>
<output>9/8 = around 1.125</output>

<gadget id="calculator">40 * (9/8)</gadget>
<output>45</output>

<gadget id="calculator">45 - 40</gadget>
<output>5</output>

<result>5</result>