In this paper we study the theory of addition chains producing any given number $n\geq 3$. With the goal of estimating the partial sums of an additive chain, we introduce the notion of the determiners and the regulators of an addition chain and prove the following identities\begin{align}\sum \limits_{j=2}^{\delta(n)+1}s_j=2(n-1)+(\delta(n)-1)+\kappa(a_{\delta(n)})-\varrho(r_{\delta(n)+1})+\int \limits_{2}^{\delta(n)-1}\sum \limits_{2\leq j\leq t}\varrho(r_j)dt\nonumber \end{align}where \begin{align}2,s_3=\kappa(a_3)+\varrho(r_3),\ldots,s_{k-1}=\kappa(a_{k-1})+\varrho(r_{k-1}),s_{k}=\kappa(a_{k})+\varrho(r_{k})=n\nonumber \end{align}are the associated generators of the chain $1,2,\ldots,s_{k-1},s_{k}=n$ of length $\delta(n)$. Also we obtain the identity\begin{align}\sum \limits_{j=2}^{\delta(n)+1}\kappa(a_j)=(n-1)+(\delta(n)-1)+\kappa(a_{\delta(n)})-\varrho(r_{\delta(n)+1})+\int \limits_{2}^{\delta(n)-1}\sum \limits_{2\leq j\leq t}\varrho(r_j)dt.\nonumber \end{align}