We give formulas for the image Milnor number of a weighted-homogeneous map-germ $$({\mathbb {C}}^n,0)\rightarrow ({\mathbb {C}}^{n+1},0)$$ , $$n=4$$ and 5, in terms weights degrees. Our expressions are obtained by purely interpolative method, applied to result Ohmoto. use our approach recover $$n=2$$ 3 due Mond Ohmoto, respectively. For $$n\ge 6$$ method is valid as long certain multi-singulari...