A takes 9 hours to transport a batch of goods. If B transports this batch of goods, B will take 10 hours. If A and B work together to transport 5 hours, then as long as 10 boxes of goods are shipped less per hour, the goods will be shipped. How many boxes are there in this batch?
甲用9小时运完一批货，如果这批货让乙运，乙要用10小时，如果甲，乙二人合作运5小时，那么只要每小时少运10箱货也正好运完．这批货有多少箱？
<gadget id="calculator">1 / 9</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/9) + (1/10)</gadget>
<output>19/90 = around 0.211111</output>

<gadget id="calculator">(19/90) * 5</gadget>
<output>19/18 = around 1.055556</output>

<gadget id="calculator">(19/18) - 1</gadget>
<output>1/18 = around 0.055556</output>

<gadget id="calculator">5 / (1/18)</gadget>
<output>90</output>

<gadget id="calculator">10 * 90</gadget>
<output>900</output>

<result>900</result>