Dear student,
Mass is the amount of matter contained in the body. So, it remains the same irrespective of the place.
Thus, the mass on the moon and earth will be the same.
But weight is the force by which the body is attracted to the earth and moon. It depends on the value of acceleration due to gravity.
We know that the gravitational pull on the moon is approximately 1/6 times that on Earth.
So, if the weight of the body on the moon is 400 N, its weight on the Earth is 400*6= 2400N.
Regards