To determine the missing number in the sequence $12, 31, 48, ?, 72, 79$, let's examine the differences between the numbers:

1. $31 - 12 = 19$
2. $48 - 31 = 17$
3. $72 - ? = ?$

It appears that the differences between terms are decreasing by 2 each time:

• $19$ for the first difference
• $17$ for the second difference

Following this pattern, the next difference should be $15$.

So, we add $48 + 15 = 63$ to find the missing term.

The missing number is $63$.

Would you like further details or have any questions?

Here are some additional related questions for practice:

1. What would be the next number in this sequence after $79$ if the pattern continues?
2. How can we determine the $n$-th term of this sequence?
3. What if the differences increased by 3 each time instead of decreasing by 2?
4. How would the sequence change if we started with a different initial number, say $20$?
5. Can you find a similar sequence where the pattern is based on multiplication instead of addition?

Tip: When working with sequences, always check for consistent differences (arithmetic sequences) or ratios (geometric sequences) between terms.