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Monday Mutant 64: Crowd Nine (equations)

In this Crowd Nine puzzle, all of the outlined equations, when read from left to right or from top to bottom, must be true when the grid is filled in. Perform operations in reading order (for example, 3-1+2 is 4, not 0, and 1+2×3 is 9, not 7). The rules are otherwise unchanged.
This puzzle was written as a follow-up to Monday Mutant 62, which was in turn a response to a puzzle submitted by a reader. The previous puzzle had symmetrical givens; this one goes a step further by having none at all.

6 comments

Blaine said...

Given the reading order evaluation you've given to the puzzle and the fact that the arithmetic operators can be flipped 180°, it would be interesting to see a version that would solve differently upside down.

ralphmerridew said...

Maybe an invertible puzzle that uses only the digits 1, 6, 8, 9 (possibly 2 and 5 if done like a digital clock).

The Grim Recapper said...

Actually, this is a really nice variant when done properly.

Rob said...

Quite fun for a Sudoku-based puzzle, thanks!

I'd prefer if you didn't use subtraction or division unless necessary, though:

a+b=c+d+e instead of a+b-c-d=e
a*b*c=d*e*f instead of a*b*c/d/e=f
a=bc/d is fine

Cheers
Robert

james39562 said...

I haven't solved it yet, but another idea is to have some equations make a 90 degree bend in it. This would allow repeats of digits in the equation.

ralphmerridew said...

A diagonal equation would also allow duplicated digits.

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