To solve for the missing number in the expression \( 7^? ÷ 7^5 = 7^{12} \), we can use the properties of exponents.
The division of powers with the same base can be expressed as:
\[ \frac{7^a}{7^b} = 7^{a-b} \]
So we can rewrite the left side:
\[ 7^? ÷ 7^5 = 7^{? - 5} \]
Now our equation looks like this:
\[ 7^{? - 5} = 7^{12} \]
Since the bases are the same, we can set the exponents equal to each other:
\[ ? - 5 = 12 \]
Now, solve for \( ? \):
\[ ? = 12 + 5 \] \[ ? = 17 \]
Therefore, the missing number is \( 17 \).