The best replacement for solver is goal seek.

The best alternatives to solver are rated as following:
★★★★★  goal seek
★★★★  dulux
★★★  oxiclean
★★  taubmans
★  crystal ball
★  segregated
★  pcg solver
  problem identifier
  evolver
  oxyclean
  mathcad
  oxy boost
  problem-solver
  oxy clean

Your alternative for solver is not listed? Suggest!
Speaking about solver, one probably shouldn't forget about macro.

Other search terms related to solver and their ratings are:
★★★★★ macro
★★★★ clues
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solver
goal seek
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