batch of wood, first use up (1/5) of the total amount, and then use up (4/9) of the total amount. At this time, the amount used is 13 square meters more than the rest. How many square meters are there in total for this batch of wood?
一批木料，先用去总数的(1/5)，又用去总数的(4/9)，这时用去的比剩下的多13方，这批木料共有多少方？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">(1/5) + (4/9)</gadget>
<output>29/45 = around 0.644444</output>

<gadget id="calculator">1 - (1/5) - (4/9)</gadget>
<output>16/45 = around 0.355556</output>

<gadget id="calculator">(29/45) - (16/45)</gadget>
<output>13/45 = around 0.288889</output>

<gadget id="calculator">13 / (13/45)</gadget>
<output>45</output>

<result>45</result>