To each Christmas tree :
- Put two $+$, two $-$, and two $×$, to the yellow triangles.
- in a row, there must be different operators (so between $[2,0,1,7]$ all $3$ operators must appear)
- $A - B$ means $|A - B|$
Both Christmas Tree must contains exactly same set of numbers including the initial numbers. If the left tree contains $[a,b,..,j]$ (including $[2,0,1,7,7]$), the right tree must also contain $[a,b,..,j]$ (including $[2,0,1,8,8]$)