Answer:
2 by 9 (2/9) times
Step-by-step explanation:
The weight of an object depends on the acceleration due to gravity of the planet on which the object is.
= Weight of sledgehammer on Earth = 18 pounds
= Weight of sledgehammer on planet Namar = 4 pounds
Dividing the values we get

So, your weight on Namar would be 2 by 9 (2/9) times your weight on Earth.