Xiao Ming and grandpa go for a walk, Xiao Ming walks around for 8 minutes, grandpa walks around for 10 minutes, they both walk in the same direction at the same time, how many minutes later they meet.
小明和爷爷去散步，小明走一圈8分钟，爷爷走一圈10分钟，两人同时同地同方向走，多少分钟后两人相遇．
<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

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

<gadget id="calculator">(1/8) - (1/10)</gadget>
<output>1/40 = around 0.025</output>

<gadget id="calculator">1 / (1/40)</gadget>
<output>40</output>

<result>40</result>