The students planted trees. The fourth grade planted 56 trees, and the fifth grade planted 21 trees three times less than the fourth grade. How many trees were planted in the fourth and fifth grades?
同学们栽树，四年级栽了56棵，五年级栽的棵数比四年级的3倍少21棵．四、五年级共栽多少棵？
<gadget id="calculator">56 * 3</gadget>
<output>168</output>

<gadget id="calculator">168 - 21</gadget>
<output>147</output>

<gadget id="calculator">147 + 56</gadget>
<output>203</output>

<result>203</result>