A chair is 60 yuan, a table is 90 yuan more expensive than a chair, and a set of sofas is 300 yuan more expensive than a table. How much is a set of sofas.
一把椅子60元，一张桌子比一把椅子贵90元，一组沙发又比一张桌子贵300元，一组沙发是多少元．
<gadget id="calculator">60 + 90 + 300</gadget>
<output>450</output>

<result>450</result>