In the sequence 1, 3, 2, .. each term after the first two is equal to the preceding term, subtracted from the term that precedes it, that is, if $n>2$, then $a_{n}=a_{n-1}-a_{n-2}$. What is the sum of the first hundred terms of this sequence?
Initially, we write the first terms of this sequence as follows.

$$
1,3,2,-1,-3,-2,1,3,2, \ldots
$$

The seventh and eighth terms are, respectively, equal to the first and second. This means that the sequence repeats every six terms. The sum of the first six terms is $1+3+2-1-3-2=0$ and, therefore, the sum of the first 96 terms is also 0. Thus, the sum of the first 100 terms of this sequence is equal to the sum of the last four terms, that is, $1+3+2-1=5$.