After subtracting 15 from Grandpa Li Gang's age, divide by 4, then subtract 6, multiply by 10 to equal 100, 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，乘以10等于100，李刚爷爷今年多少岁．
<gadget id="calculator">100 / 10</gadget>
<output>10</output>

<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>