Wednesday and Thursday were so-called "Binary Days", dates for which the month, day, and (two-digit) year could all be expressed with just the digits 1 and 0 so that the date appeared as an apparent binary string. I personally mark such dates with the level of significance I'd give, say, Pi day or Mole day, which is to say approximately zero. But from time to time these "special" days can inspire a puzzle, as Square Root Day inspired the first calcudoku I wrote over a year ago, themed around the number three.

Unfortunately, I release new puzzles on Friday and this Friday is not a Binary Day. But my mind likes taking things to extremes, and in a world in which Binary Days have some significance, there would be a slightly less uncommon but still interesting occurrence today as 11/12/2010 is what one could call a "Ternary Date" using just the digits 0, 1, and 2. And unlike all binary dates since the year 1111, you can actually celebrate this ternary date using the full year, making it extra special. I thought I'd take appearing like ternary to an odd extreme in today's 75th Friday Puzzle. Each of these calcu-doku puzzles looks like it is in base three, in the clues and in the number sets, but both are actually solved in base ten.

Rules: Enter a number into each cell using the set of numbers below the grid so that no number repeats in any row or column. The number in the upper-left of each bolded cage must equal the value of a mathematical operation (+, -, x, /) applied to the digits in the cage starting from the largest number, with multi-cell subtraction and division (such as 2-1-0 = 1) possible in these calcu-doku. In the first puzzle, the operations are not given to you but at least one must be correct when applied to each cage. Division by 0 is not allowed.

Unfortunately, I release new puzzles on Friday and this Friday is not a Binary Day. But my mind likes taking things to extremes, and in a world in which Binary Days have some significance, there would be a slightly less uncommon but still interesting occurrence today as 11/12/2010 is what one could call a "Ternary Date" using just the digits 0, 1, and 2. And unlike all binary dates since the year 1111, you can actually celebrate this ternary date using the full year, making it extra special. I thought I'd take appearing like ternary to an odd extreme in today's 75th Friday Puzzle. Each of these calcu-doku puzzles looks like it is in base three, in the clues and in the number sets, but both are actually solved in base ten.

Rules: Enter a number into each cell using the set of numbers below the grid so that no number repeats in any row or column. The number in the upper-left of each bolded cage must equal the value of a mathematical operation (+, -, x, /) applied to the digits in the cage starting from the largest number, with multi-cell subtraction and division (such as 2-1-0 = 1) possible in these calcu-doku. In the first puzzle, the operations are not given to you but at least one must be correct when applied to each cage. Division by 0 is not allowed.

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