Write the following using a letter
The sum of a certain number and 3.

Explanation

To write the expression "The sum of a certain number and 3" using a letter, we can follow these steps:

### Step 1: Define the variable
Let’s denote the certain number by a letter. We can use the letter \( x \) to represent this number.

### Step 2: Write the expression for the sum
The phrase "the sum of a certain number and 3" means we need to add 3 to the number we defined. Therefore, we write this as:

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