The average age of the four grandparents is 70 years old. Among them, Grandpa Li is 65 years old, Grandpa Zhang is 55 years old, and Grandpa Chen is 70 years old. How old is Grandpa Zhao?
四位爷爷的平均年龄70岁．其中李爷爷有65岁，张爷爷55岁、陈爷爷70岁，请问赵爷爷有几岁了？
<gadget id="calculator">70 * 4</gadget>
<output>280</output>

<gadget id="calculator">65 + 55 + 70</gadget>
<output>190</output>

<gadget id="calculator">280 - 190</gadget>
<output>90</output>

<result>90</result>