Naughty went to the stationery store and bought a pen for 3.5 yuan and a ruler for 1.8 yuan. How much did he have to pay in total?
淘气去文具店买了一支钢笔花了3.5元，一把直尺花了1.8元，他一共要付多少钱？
<gadget id="calculator">3.5 + 1.8</gadget>
<output>5.3</output>

<result>5.3</result>