There are 4 classes in the third grade, and an average of 106 trees are planted per class during the Arbor Day; there are 3 classes in the fourth grade, and a total of 450 trees are planted during the Arbor Day. How many trees were planted in the third and fourth grades?
三年级有4个班，植树节期间平均每班植树106棵；四年级有3个班，植树节期间一共植树450棵．三、四年级一共植树多少棵？
<gadget id="calculator">4 * 106</gadget>
<output>424</output>

<gadget id="calculator">3 * 450</gadget>
<output>1_350</output>

<gadget id="calculator">424 + 1_350</gadget>
<output>1_774</output>

<result>1_774</result>