Abstract: In this study, the notion of βδ-reduction for main canonical notion of δ-reduction is considered. Typed λ-terms use variables of any order and constants of order ≤1 where constants of order 1 are strongly computable, monotonic functions with indeterminate values of arguments. The canonical notion of δ-reduction is the notion of δ-reduction that is used in the implementation of functional programming languages. For main canonical notion of δ-reduction the uniqueness of βδ-normal form of typed λ-terms is shown.