A total of 270 trees were planted in the leisure park last year and this year, and 150 trees were planted this year. How many trees were planted last year?
休闲公园去年和今年共植树270棵，今年植树150棵，去年植树多少棵？
<gadget id="calculator">270 - 150</gadget>
<output>120</output>

<result>120</result>