Weight = (mass) x (gravity)
From this simple formula for weight, you can see that
an object's weight is directly proportional to the acceleration
of gravity in the place where the object is located.
If the object weighs 350 N on Earth and 134 N on Mars, then
we can write
(9.8 m/s²) / 350 = (Mars gravity) / 134
Multiply each side by 134:
Mars gravity = (134/350) x (9.8 m/s²)
Mars gravity = 3.75 m/s²
(The official, accepted value is 3.71 m/s² .)