Fibonacci Extended

Choose two whole numbers (number one and number two). Add them together and form a Fibonacci-like sequence (add number one and number two together to get number three, then add number two and number three together to get number four, etc.). End with a total of ten numbers. Repeat the process by starting with two different numbers. What is the relationship between the seventh term and the sum of the terms (for each sequence)? What is the relationship between the seventh term and the tenth term (for each sequence)? Explain.

Extension
Would your result be different if you started with negative numbers or fractions?