How to make a 4% baking soda solution?

The mass fraction of soda in solution is the ratio of its mass (solute) m (r.v) to the mass of the solution m (r-ra):
w = m (r.v) / m (r-ra)
Let us express from the formula m (r.v.) = W * m (r-ra)
The mass of the solution, in turn, is made up of the mass of soda and the mass of the solvent m (r-la):
m (r-pa) = m (r.v) + m (r-la), m (r-la) = m (p-pa) – m (r.v.)
Let’s decide how much solution we want to get. For example, for the convenience of calculations, we will take 100 g.
Then the mass of soda m (r.v.) = 0.04 * 100 = 4 g.
Determine the amount of water: m (r-la) = 100 – 4 = 96 g
Thus, it turns out that to obtain a 4% solution of soda, for every 96 g of water, you need to take 4 g of soda