Task cards for practicing addition of fractions with denominators 10 and 100, aligned with 4.NF.5 standard.

Let’s solve each problem step by step.

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Problem 17:
We need to add:
18/100 + 3/10

First, make the denominators the same.
The second fraction is 3/10. To turn it into hundredths, multiply numerator and denominator by 10:
→ 3 × 10 = 30
→ 10 × 10 = 100
So, 3/10 = 30/100

Now add:
18/100 + 30/100 = (18 + 30)/100 = 48/100

We can simplify if needed, but since the question just says “find the sum,” we’ll leave it as 48/100 unless told otherwise. But let’s check if it reduces:
48 and 100 are both divisible by 4 → 48 ÷ 4 = 12, 100 ÷ 4 = 25 → 12/25

But looking at the other problems, they seem to expect answers in hundredths or simplified? Let’s see what makes sense with the others. Actually, for now, we’ll keep it as 48/100, but note that 12/25 is also correct. However, since all problems use denominators of 10 or 100, maybe they want the answer over 100. We’ll go with 48/100 for consistency — but wait, let’s check the next ones.

Actually, let’s do them all first and then decide.

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Problem 18:
4/10 + 26/100

Convert 4/10 to hundredths:
4 × 10 = 40, 10 × 10 = 100 → 40/100

Add:
40/100 + 26/100 = 66/100

That’s straightforward.

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Problem 19:
8/10 + 5/100

Convert 8/10 to hundredths:
8 × 10 = 80, 10 × 10 = 100 → 80/100

Add:
80/100 + 5/100 = 85/100

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Problem 20:
17/100 + 6/10

Convert 6/10 to hundredths:
6 × 10 = 60, 10 × 10 = 100 → 60/100

Add:
17/100 + 60/100 = 77/100

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Now, going back to Problem 17:
We had 48/100. Should we reduce it? The other answers are 66/100, 85/100, 77/100 — none of those reduce nicely except maybe 85/100 (divisible by 5 → 17/20), but again, since the problems are about adding fractions with denominators 10 and 100, and the standard is to write the sum over 100, I think we should leave all answers over 100 unless specified.

But let me double-check: In many curricula, when you’re learning to add tenths and hundredths, they expect the answer in hundredths form, even if reducible. So we’ll present all as over 100.

Wait — actually, looking at the format, the problems don’t specify to simplify, so safest is to give the sum as is after converting to common denominator.

So:

- 17: 48/100
- 18: 66/100
- 19: 85/100
- 20: 77/100

But let me verify calculations once more:

17: 18/100 + 3/10 = 18/100 + 30/100 = 48/100 ✔
18: 4/10 + 26/100 = 40/100 + 26/100 = 66/100 ✔
19: 8/10 + 5/100 = 80/100 + 5/100 = 85/100 ✔
20: 17/100 + 6/10 = 17/100 + 60/100 = 77/100 ✔

All correct.

Final Answer:
17. 48/100
18. 66/100
19. 85/100
20. 77/100

But perhaps they want simplified forms? Let’s check if any reduce easily:

- 48/100 = 12/25 (divide by 4)
- 66/100 = 33/50 (divide by 2)
- 85/100 = 17/20 (divide by 5)
- 77/100 = already simplified (77 and 100 share no common factors)

Hmm. Since the original problems mix 10s and 100s, and the instruction is “find the sum,” not “simplify,” I think either form is acceptable. But to match the style of the problems (which show denominators 10 and 100), and since the sums naturally come out over 100, I’ll present them over 100.

However, in many textbooks, they might expect simplified form. But without explicit instruction, and since the user didn’t ask to simplify, I’ll go with the unsimplified hundredths form for consistency.

Alternatively, maybe the expected answer is decimal? But the problems are written as fractions, so probably not.

Looking again at the image description — it's from a worksheet labeled "4.NF.5" which is a Common Core standard about expressing fractions with denominator 10 as equivalent fractions with denominator 100, and adding them. So the goal is to get the sum as a fraction over 100.

Therefore, final answers should be over 100.

Final Answer:
17. \frac{48}{100}
18. \frac{66}{100}
19. \frac{85}{100}
20. \frac{77}{100}

But to write them neatly:

Since the user might expect boxed answers or listed clearly, I'll list them as:

For problem 17: 48/100
For problem 18: 66/100
For problem 19: 85/100
For problem 20: 77/100

But in the Final Answer section, I need to provide only the final correct answer — so I’ll list all four.

Actually, the instruction says: “Provide only the final correct answer — this should come AFTER all explanations and reasoning.” And since there are four separate problems, I should provide all four answers.

I think the best way is to list them as:

17. \frac{48}{100}
18. \frac{66}{100}
19. \frac{85}{100}
20. \frac{77}{100}

But to be precise, let me confirm once more:

Problem 17: 18/100 + 3/10 = 18/100 + 30/100 = 48/100 ✔️
Problem 18: 4/10 + 26/100 = 40/100 + 26/100 = 66/100 ✔️
Problem 19: 8/10 + 5/100 = 80/100 + 5/100 = 85/100 ✔️
Problem 20: 17/100 + 6/10 = 17/100 + 60/100 = 77/100 ✔️

All correct.

Final Answer:
17. \frac{48}{100}
18. \frac{66}{100}
19. \frac{85}{100}
20. \frac{77}{100}