1. The problem is to find the missing terms in a sequence or expression. 2. To find missing terms, we often use formulas depending on the type of sequence: arithmetic, geometric, or others. 3. For an arithmetic sequence, the formula for the $n$th term is $$a_n = a_1 + (n-1)d$$ where $a_1$ is the first term and $d$ is the common difference. 4. For a geometric sequence, the formula is $$a_n = a_1 \times r^{n-1}$$ where $r$ is the common ratio. 5. Identify the known terms and the pattern to determine $d$ or $r$. 6. Use the formula to calculate the missing terms by substituting the values. 7. If the problem is different, please provide the sequence or expression to find the missing terms specifically.