Add:
`8ab, - 5ab, 3ab, - ab`

Answer

To solve the problem of adding the algebraic expressions \( 8ab, -5ab, 3ab, -ab \), we will follow these steps:

### Step 1: Identify and group the like terms
We have the terms:
- Positive terms: \( 8ab \) and \( 3ab \)
- Negative terms: \( -5ab \) and \( -ab \)

### Step 2: Add the positive terms
Now, we will add the positive terms together:
\[ 8ab + 3ab = 11ab \]

### Step 3: Add the negative terms
Next, we will add the negative terms together:
\[ -5ab + (-ab) = -5ab - 1ab = -6ab \]

### Step 4: Combine the results from Step 2 and Step 3
Now, we will combine the results from the positive and negative sums:
\[ 11ab + (-6ab) = 11ab - 6ab = 5ab \]

### Step 5: Determine the sign of the final result
Since \( 11ab \) (the positive sum) is greater than \( 6ab \) (the absolute value of the negative sum), the final result will be positive:
\[ 5ab \]

### Final Answer
Thus, the sum of the algebraic expressions \( 8ab, -5ab, 3ab, -ab \) is:
\[ \boxed{5ab} \]