On Arbor Day, the sixth grade planted 45 trees, and the fifth grade planted 9 fewer trees than the sixth grade. How many trees were planted in the fifth and sixth grades?
植树节上，六年级植树45棵，五年级比六年级少植9棵．五、六年级一共植树多少棵？
<gadget id="calculator">45 - 9</gadget>
<output>36</output>

<gadget id="calculator">36 + 45</gadget>
<output>81</output>

<result>81</result>