Finding Atomic Mass Unit by Subatomic Particles

[onurbeyaz]

If one atomic mass unit is 1/12 of a C-12 atom, so 1 amu must be;

1 Amu = 1/2 ( Mass of proton + Mass of neutron + Mass of electron )

But the equation gives the answers that 1 amu is 1,6737 10^(-27) kg, which is different than the internet says
I am using very sensitive values for the equation so why am I finding nearly %1 error

 

[Borek]

1 amu must be;

1 Amu = 1/2 ( Mass of proton + Mass of neutron + Mass of electron )

No, it doesn't have to be that.

Google "mass deficit" or "binding energy".