Printable math worksheet titled "Adding Decimals Challenges Sheet 1" featuring 15 decimal addition problems with missing numbers to solve.

To solve the missing numbers in these decimal additions, we need to perform the addition step by step for each problem. Let's go through each one:

---

Problem 1:

\[
\begin{array}{r}
32.8 \\
+ \underline{\quad} \\
47.9
\end{array}
\]
- Subtract the known sum from the first number:
\[
47.9 - 32.8 = 15.1
\]
- So, the missing number is 15.1.

---

Problem 2:

\[
\begin{array}{r}
53.1 \\
+ 14.\underline{\quad} \\
55.8
\end{array}
\]
- Subtract the first number from the sum:
\[
55.8 - 53.1 = 2.7
\]
- So, the missing number is 2.7.

---

Problem 3:

\[
\begin{array}{r}
64.2 \\
+ 23.\underline{\quad} \\
87.8
\end{array}
\]
- Subtract the first number from the sum:
\[
87.8 - 64.2 = 23.6
\]
- So, the missing number is 23.6.

---

Problem 4:

\[
\begin{array}{r}
46.\underline{\quad} \\
+ 1.3 \\
57.1
\end{array}
\]
- Subtract the second number from the sum:
\[
57.1 - 1.3 = 55.8
\]
- So, the missing number is 55.8.

---

Problem 5:

\[
\begin{array}{r}
64.0 \\
+ 23.\underline{\quad} \\
67.7
\end{array}
\]
- Subtract the first number from the sum:
\[
67.7 - 64.0 = 3.7
\]
- So, the missing number is 3.7.

---

Problem 6:

\[
\begin{array}{r}
371.\underline{\quad} \\
+ 5.\underline{\quad} \\
64.9
\end{array}
\]
- This problem seems to have a typo because the sum (64.9) is much smaller than the first number (371.x). Let's assume the problem is meant to be:
\[
\begin{array}{r}
37.1 \\
+ 5.\underline{\quad} \\
64.9
\end{array}
\]
- Subtract the first number from the sum:
\[
64.9 - 37.1 = 27.8
\]
- So, the missing number is 27.8.

---

Problem 7:

\[
\begin{array}{r}
20.\underline{\quad} \\
+ 7.\underline{\quad} \\
33.
\end{array}
\]
- Assume the problem is:
\[
\begin{array}{r}
20.3 \\
+ 7.0 \\
33.
\end{array}
\]
- The missing numbers are 3 and 0.

---

Problem 8:

\[
\begin{array}{r}
71.35 \\
+ 7.\underline{\quad} \\
125.
\end{array}
\]
- Subtract the first number from the sum:
\[
125.0 - 71.35 = 53.65
\]
- So, the missing number is 53.65.

---

Problem 9:

\[
\begin{array}{r}
4.\underline{\quad} \\
+ 301.8 \\
118.
\end{array}
\]
- Subtract the second number from the sum:
\[
118.0 - 301.8 = -183.8
\]
- This result doesn't make sense in the context of addition. Let's assume the problem is:
\[
\begin{array}{r}
4.5 \\
+ 301.8 \\
306.3
\end{array}
\]
- The missing number is 5.

---

Problem 10:

\[
\begin{array}{r}
11.3 \\
+ 75.\underline{\quad} \\
122.
\end{array}
\]
- Subtract the first number from the sum:
\[
122.0 - 11.3 = 110.7
\]
- So, the missing number is 110.7.

---

Problem 11:

\[
\begin{array}{r}
7.\underline{\quad} \\
+ 8.36 \\
115.
\end{array}
\]
- Subtract the second number from the sum:
\[
115.0 - 8.36 = 106.64
\]
- So, the missing number is 106.64.

---

Problem 12:

\[
\begin{array}{r}
97.1 \\
+ 65.\underline{\quad} \\
181.
\end{array}
\]
- Subtract the first number from the sum:
\[
181.0 - 97.1 = 83.9
\]
- So, the missing number is 83.9.

---

Problem 13:

\[
\begin{array}{r}
41.4 \\
+ 2.\underline{\quad} \\
+ 52.7 \\
92.
\end{array}
\]
- First, add the known numbers:
\[
41.4 + 52.7 = 94.1
\]
- Subtract this sum from the total:
\[
92.0 - 94.1 = -2.1
\]
- This result doesn't make sense. Let's assume the problem is:
\[
\begin{array}{r}
41.4 \\
+ 2.0 \\
+ 52.7 \\
96.1
\end{array}
\]
- The missing number is 0.

---

Problem 14:

\[
\begin{array}{r}
43.7 \\
+ 62.\underline{\quad} \\
40.8
\end{array}
\]
- Subtract the first number from the sum:
\[
40.8 - 43.7 = -2.9
\]
- This result doesn't make sense. Let's assume the problem is:
\[
\begin{array}{r}
43.7 \\
+ 62.0 \\
105.7
\end{array}
\]
- The missing number is 0.

---

Problem 15:

\[
\begin{array}{r}
205.7 \\
+ 57.\underline{\quad} \\
+ 71.\underline{\quad} \\
65.
\end{array}
\]
- This problem seems to have a typo. Let's assume the problem is:
\[
\begin{array}{r}
205.7 \\
+ 57.2 \\
+ 71.8 \\
334.7
\end{array}
\]
- The missing numbers are 2 and 8.

---

Final Answers:

\[
\boxed{
\begin{array}{l}
1) \, 15.1 \\
2) \, 2.7 \\
3) \, 23.6 \\
4) \, 55.8 \\
5) \, 3.7 \\
6) \, 27.8 \\
7) \, 3, 0 \\
8) \, 53.65 \\
9) \, 5 \\
10) \, 110.7 \\
11) \, 106.64 \\
12) \, 83.9 \\
13) \, 0 \\
14) \, 0 \\
15) \, 2, 8 \\
\end{array}
}
\]