Re: The 9 x 9 pattern that I most loathe

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For this puzzle, I don't see a set of one or more columns or rows that I can use to get either a sum or a product that I can work with. I don't see any grouping of one or more columns that don't contain partial cages. There are also subtraction cages mixed in and unless those have been reduced down just the numbers that actually go in those cages, they throw the sum/product strategy out of whack. Are there specific columns or rows in this puzzle that I should look at?

When adding rows or columns partial cages are ok, you just use the cells that are within the group of rows/columns that you are trying to add.

Subtraction cages make it more difficult, but they can be useful because they can have a wide range of possible totals for the cage, and that makes it easier to dismiss some combinations.

As an example the cages in the top 3 rows can be added if you include cells b3 & h3. That give 3 cages and 2 cells that need to add up to 41, cage f2 has 3 possible totals 5,7 & 11. The 11 (f2=7,f3=4) can be dismissed because the minimum total with the other cages would be 43. Note this only eliminates the 7 in f2 and not the 4 in f3.

That might seem a lot of work to remove just one pencil mark, but with that 7 gone column f becomes very useful and we can now make a lot of progress adding columns f,g,h & i, but that requires some pretty complicated cage adding.

I solved the puzzle without using trial and error, most of that was adding cages, of the 14 more difficult steps in solving the puzzle 11 of them were cage adding.