To find the missing step using the Commutative Property, we need to rearrange the terms in the expression \(12a + 10 + a\).
The Commutative Property states that the order in which you add numbers does not change the sum.
Starting from the original expression \(12a + 10 + a\), we can rearrange it as:
Step 1: \(10 + 12a + a = 10 + 13a\)
Then we can combine like terms to reach Step 2, which is \(10 + 13a = 10 + 13a\).
The answer is: 10 + 12a + a = 10 + 13a.