Find your mass if a scale on earth reads 650 N when you stand on it.

Weight = (mass) x (acceleration of gravity).

On Earth, acceleration of gravity is 9.8 m/s² (rounded).

650 N = (mass) x (9.8 m/s²)

Divide each side by (9.8 m/s²) : 650 N / 9.8 m/s² = mass

Mass = 66.3 kilograms (rounded)