There is a barrel of oil, (1/3) is used on the first day, (1/4) is used on the second day, exactly 70kg is used in two days. How many kilograms is this barrel of oil originally?
有一桶油，第一天用去(1/3)，第二天用去(1/4)，两天正好用去70kg．这桶油原有多少千克？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/3) + (1/4)</gadget>
<output>7/12 = around 0.583333</output>

<gadget id="calculator">70 / (7/12)</gadget>
<output>120</output>

<result>120</result>