6) The Fibonacci Sequence 1, 1, 2, 3, 5, 8, 13, 21, . . . starts with two 1s and each term afterwards is the sum of its predecessors. Which one of the ten digits is the last to appear in the units position of a number in the Fibonacci Sequence?
Based on the elements listed, the digits in the units position are 1, 2, 3, 5, and 8. Let's list the next 20 terms in this sequence to see which of the digits 0, 4, 6, 7, and 9 would come last.
1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765, 10946, 17711, 28657, 46368, 75025, ...Â
In the units position for the next 20 elements, the digits appear for the first time in the order 4, 9, 7 then 0. Thus 6 is the last digit to appear in the units position.