Shi Haoran's weight is 42kg, his cousin's weight is half of his, and his grandfather's weight is 4 times that of his cousin's. How many kilograms does grandpa weigh?
石浩然体重42kɡ，表弟体重是他的一半，而爷爷体重是表弟的4倍．爷爷体重是多少千克？
<gadget id="calculator">42 / 2</gadget>
<output>21</output>

<gadget id="calculator">21 * 4</gadget>
<output>84</output>

<result>84</result>