The snacks sold in small stalls around the school are called "5jiao snacks". Among them, the weight marked on the package of a 5-corner snack is 90 grams, but it is weighed by an electronic scale as 0.060 kilograms. How many kilograms is the difference between the marked weight and the actual weight.
学校周边的小摊子卖的零食称为"5角零食"．其中有一种5角零食包装上标示的重是90克，但用电子秤称是0.060千克，标示的重量与实际重量相差多少千克．
<gadget id="calculator">90 / 1_000</gadget>
<output>9/100 = around 0.09</output>

<gadget id="calculator">(9/100) - 0.06</gadget>
<output>0.03</output>

<result>0.03</result>