After subtracting 15 from the age of Grandpa Li Gang, divide by 4, and then subtract 6, it is equal to 10. How old is Grandpa Li Gang this year?
李刚爷爷的年龄减去15后，除以4，再减去6后，等于10，李刚爷爷今年多少岁．
<gadget id="calculator">10 + 6</gadget>
<output>16</output>

<gadget id="calculator">16 * 4</gadget>
<output>64</output>

<gadget id="calculator">64 + 15</gadget>
<output>79</output>

<result>79</result>