Master Peng planned to overhaul 270 sets of tables and chairs. The planned ones were overhauled (2/3) in the first week, and the planned ones (4/15) were overhauled in the second week. How many sets of tables and chairs are left unrepaired?
彭师傅计划检修桌椅270套，第一周检修了计划的(2/3)，第二周检修了计划的(4/15)，还有多少套桌椅没有修？
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">4 / 15</gadget>
<output>4/15 = around 0.266667</output>

<gadget id="calculator">1 - (2/3) - (4/15)</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">270 * (1/15)</gadget>
<output>18</output>

<result>18</result>