Xiaoyu's family bought a bottle of oil and used about 1/21 of this bottle of oil every day. What fraction of this bottle of oil was used in 7 days? How many
小玉家买来一瓶油，每天约用这瓶油的(1/21)，7天大约用了这瓶油的几分之几？多少
<gadget id="calculator">1 / 21</gadget>
<output>1/21 = around 0.047619</output>

<gadget id="calculator">(1/21) * 7</gadget>
<output>1/3 = around 0.333333</output>

<result>1/3 = around 0.333333</result>