Place Value Problem: Convert 7 Tens and 8 Units to a Number

The problem states that we have 7 tens and 8 units. We'll use the place value or decimal structure of numbers to identify what number this represents.

In the decimal system, the value of a digit is determined by its position. A "ten" is simply the digit multiplied by 10, as the tens place is the second position from the right.

Let's break this down:

• We have 7 tens, which equates to $7 \times 10 = 70$.
• We also have 8 units, which simply contributes $8$ to the number.

To find the whole number, we need to add these values together:

$70 \, (\text{from tens}) + 8 \, (\text{from units}) = 78.$

Therefore, the number is 78.

Checking against the provided answer choices, the correct choice is:

• Option 2: $78$.

So, the number you are is $78$.