A piece of square steel is 4 meters long and its cross section is a square with side length 5 centimeters. It is known that 1 cubic centimeter of steel weighs 7.8 grams. How many kilograms does this piece of square steel weigh?
一段方钢，长4米，横截面是一个边长为5厘米的正方形．已知1立方厘米的钢重7.8克，这段方钢重多少千克？
<gadget id="calculator">5 * 5 * 4 * 100</gadget>
<output>10_000</output>

<gadget id="calculator">10_000 / 1_000</gadget>
<output>10</output>

<gadget id="calculator">7.8 * 10</gadget>
<output>78</output>

<result>78</result>