The sum of the numbers in a diagonal line downward are the first numbers of the Fibonnacci Sequence.

Example: 1 is alone so = 1, then the next would also be 1 = to 1, then 1 and 1 = 2, 2 and 1 = 3, 1 and 3 and 1 = 5, 3 and 4 and 1 = 8, 1 and 6 and 5 and 1 = 13, this can be done all the way down the triangle (as the triangle gets bigger it gets a little confusing, so make sure you color out the numbers you have already used).

Now take the = numbers like this: 1 + 1= the next number 2. 1 + 2 = the next number 3, 2+3 = the next number 5, 3 + 5 = the next number 8, so forth and so on.

By the way Fibonacci’s sequence were used to describe a curve found in many string instruments.