Addition with Tens Units: Finding Number Pairs That Sum to 55

To solve this problem, we need to find an addition exercise using tens units that totals 55. Let's work through the steps:

• Step 1: Identify the largest tens unit less than or equal to 55. The closest one is 50.
• Step 2: Determine how much more is needed to reach 55. This is $55 - 50 = 5$.
• Step 3: Add the tens unit 50 and the additional units 5 together. This results in $50 + 5 = 55$.

We conclude that the correct addition exercise is $50 + 5$, which is option choice id="3".

Therefore, the solution to the problem is:

$50+5$