Addition with Place Value: Finding Number Pairs That Sum to 98

Which addition exercise using tens and units results in 98?

To solve which addition exercise using tens and units results in 98, we will proceed with these steps:

• List the tens values we will consider: 10, 20, 30, 40, 50, 60, 70, 80, 90.
• For each tens value, subtract it from 98 to find the corresponding units needed.
• Verify which combination sums correctly to 98.

Let's examine each possibility:

- 10 + $x$ = 98 → $x = 98 - 10 = 88$ (not a unit, so invalid)
- 20 + $x$ = 98 → $x = 98 - 20 = 78$ (not a unit, so invalid)
- 30 + $x$ = 98 → $x = 98 - 30 = 68$ (not a unit, so invalid)
- 40 + $x$ = 98 → $x = 98 - 40 = 58$ (not a unit, so invalid)
- 50 + $x$ = 98 → $x = 98 - 50 = 48$ (not a unit, so invalid)
- 60 + $x$ = 98 → $x = 98 - 60 = 38$ (not a unit, so invalid)
- 70 + $x$ = 98 → $x = 98 - 70 = 28$ (not a unit, so invalid)
- 80 + $x$ = 98 → $x = 98 - 80 = 18$ (not a unit, so invalid)
- 90 + $x$ = 98 → $x = 98 - 90 = 8$ (This works, as 8 is a unit)

Thus, the addition exercise $90 + 8 = 98$ correctly adds to 98.

Therefore, the solution to the problem is: $90 + 8$.

The correct choice from the given options is: Choice 4: $90 + 8$