There are 450 tons of cement in the construction site, (1/5) of the total amount is used for the first time, and (1/9) of the total amount is used for the second time. How many tons are used in two times?
建筑工地有水泥450吨，第一次用去总数的(1/5)，第二次用去总数的(1/9)．两次一共用去多少吨．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">450 * (1/5)</gadget>
<output>90</output>

<gadget id="calculator">1 / 9</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">450 * (1/9)</gadget>
<output>50</output>

<gadget id="calculator">90 + 50</gadget>
<output>140</output>

<result>140</result>