A black-and-white TV set costs 450 yuan, and a color TV set costs 900 yuan. How much does it cost to buy three color TV sets and two black-and-white TV sets?
一台黑白电视机450元，一台彩色电视机900元，买三台彩色电视机和两台黑白电视机共用多少钱？
<gadget id="calculator">450 * 2</gadget>
<output>900</output>

<gadget id="calculator">900 * 3</gadget>
<output>2_700</output>

<gadget id="calculator">900 + 2_700</gadget>
<output>3_600</output>

<result>3_600</result>