- 20 Aug '07 21:58 / 1 editStart with four numbers:

a b c d

Fill in subsequent rows by taking the absolute value of the number above minus the one above and to the right:

|a-b| |b-c| |c-d| |d-a| (d has nothing to the right, so we 'wrap around' and use a)

The challenge is:**Find numbers a, b, c, and d that yield 20 rows where at least one number on each row is not zero. (not counting the initial row)**

Example:

If we start with 1, 2, 3, 4, we get:

1 1 1 3

0 0 2 2

0 2 0 2

2 2 2 2

0 0 0 0

This counts as 4 iterations. - 20 Aug '07 22:12

100, 3, 2, 1*Originally posted by SwissGambit***Start with four numbers:**

a b c d

Fill in subsequent rows by taking the absolute value of the number above minus the one above and to the right:

|a-b| |b-c| |c-d| |d-a| (d has nothing to the right, so we 'wrap around' and use a)

The challenge is: [b]Find numbers a, b, c, and d that yield 20 rows where at least one number on each row is not ...[text shortened]... 2, 3, 4, we get:

1 1 1 3

0 0 2 2

0 2 0 2

2 2 2 2

0 0 0 0

This counts as 4 iterations.

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did I understqnd the question right? - 20 Aug '07 22:27 / 1 edit

Using those numbers, i get*Originally posted by agryson***100, 3, 2, 1**

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did I understqnd the question right?

100 3 2 1

97 1 1 99

96 0 98 2

96 98 96 94

2 2 2 2

0 0 0 0

...which is only 4 iterations.

Order of operations is to subtract first, and then take the absolute value of that result. - 22 Aug '07 04:16

Who says they are letters?*Originally posted by Gastel***The mistake is a b c and d are letters not numbers!!!**

HA HA HA!

He says from the beginning: "Start with four numbers: a b c d"

If he says the symbols are numbers they are, believe me. They perhaps look like letters but they are in fact numbers.

Can you solve the equation 2x=4 not realizing that the x stands for a number?