The third grade of Dongshan Primary School planted 56 trees, the fourth grade planted twice as many trees as the third grade, and the fifth grade planted 7 fewer trees than the third and fourth grades. How many trees are planted in fifth grade?
东山小学三年级植树56棵，四年级植的是三年级的2倍，五年级植的比三、四年级的总数少7棵．五年级植树多少棵？
<gadget id="calculator">56 * 2</gadget>
<output>112</output>

<gadget id="calculator">56 - 7</gadget>
<output>49</output>

<gadget id="calculator">112 + 49</gadget>
<output>161</output>

<result>161</result>