perplexus.info :: Numbers : Puzzle Strips 2

Puzzle Strips 2 (Posted on 2003-12-22)

The numbers and symbols below are placed onto six vertical strips of paper:

        8    -    2    9    ×    1
        +    1    =    5    1    5
        =    9    0    2    ÷    6
        1    =    5    6    =    1

Rotate and rearrange the strips so that four valid equations appear across the rows.

Note: Consider the numbers as they appear on a digital watch; 0, 1, 2, 5 and 8 are the same when rotated 180°, while 6 and 9 rotate to each other.

Submitted by DJ

Rating: 4.2857 (7 votes)

Solution: (Hide)

1 8 = 2 × 9 9 + 6 = 1 5 5 = 1 0 ÷ 2 1 1 - 5 = 6
We start out with:
8 - 2 9 × 1 + 1 = 5 1 5 = 9 0 2 ÷ 6 1 = 5 6 = 1
First, notice that since each there are six characters to a line, and only four operations, each row must contain a two-digit number.
The first row needs an equals sign in order to make a complete equation, and the bottom one has two. That means the second or fifth strip needs to be rotated.
Let's try flipping the second one:
8 = 2 9 × 1 + 6 = 5 1 5 = 1 0 2 ÷ 6 1 - 5 6 = 1
The first line, now, seems to lend itself to an equation:
1 8 = 2 × 9 5 + 6 = 1 5 6 = 1 0 ÷ 2 1 1 - 5 = 6
That also allows the bottom row to work; the middle two do not. Simple inspection shows that flipping the first strip solves the puzzle:
1 8 = 2 × 9 9 + 6 = 1 5 5 = 1 0 ÷ 2 1 1 - 5 = 6

Comments: ( You must be logged in to post comments.)

Subject	Author	Date
Puzzle Thoughts	K Sengupta	2023-06-16 00:00:23
Uniqueness Verification (by hand)	nikki	2005-01-07 19:41:56
re: One Solution -- verification of uniqueness	Charlie	2003-12-22 18:52:44
One Solution	stan	2003-12-22 08:43:59

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