Doudou has 70 stamps, and Miaomiao has three times as many stamps as Doudou. How many stamps do they have together?
豆豆有70张邮票，苗苗邮票的张数是豆豆的3倍，两人一共有多少张邮票？
<gadget id="calculator">70 * 3</gadget>
<output>210</output>

<gadget id="calculator">210 + 70</gadget>
<output>280</output>

<result>280</result>