Math worksheet for practicing addition of decimals with regrouping and missing numbers.

Problem: Solve the addition sentences involving tenths and hundredths with regrouping, filling in the missing numbers.

#### Step-by-Step Solution:

1. 0.97 + ☐ = 1.67
- To find the missing number, subtract 0.97 from 1.67:
\[
1.67 - 0.97 = 0.70
\]
- The missing number is 0.70.

2. ☐ + 0.94 = 1.34
- To find the missing number, subtract 0.94 from 1.34:
\[
1.34 - 0.94 = 0.40
\]
- The missing number is 0.40.

3. 4.1 + 3.99 = ☐
- Add 4.1 and 3.99:
\[
4.1 + 3.99 = 8.09
\]
- The result is 8.09.

4. ☐ + 1.7 = 3.58
- To find the missing number, subtract 1.7 from 3.58:
\[
3.58 - 1.7 = 1.88
\]
- The missing number is 1.88.

5. 2.8 + ☐ = 8.79
- To find the missing number, subtract 2.8 from 8.79:
\[
8.79 - 2.8 = 5.99
\]
- The missing number is 5.99.

6. 2.39 + 4.8 = ☐
- Add 2.39 and 4.8:
\[
2.39 + 4.8 = 7.19
\]
- The result is 7.19.

7. 13.90 + 19.0 = ☐
- Add 13.90 and 19.0:
\[
13.90 + 19.0 = 32.90
\]
- The result is 32.90.

8. 29.3 + ☐ = 92.80
- To find the missing number, subtract 29.3 from 92.80:
\[
92.80 - 29.3 = 63.50
\]
- The missing number is 63.50.

9. 15.9 + ☐ = 52.62
- To find the missing number, subtract 15.9 from 52.62:
\[
52.62 - 15.9 = 36.72
\]
- The missing number is 36.72.

10. ☐ + 37.3 = 87.11
- To find the missing number, subtract 37.3 from 87.11:
\[
87.11 - 37.3 = 49.81
\]
- The missing number is 49.81.

Final Answers:

\[
\boxed{
\begin{aligned}
&0.70 \\
&0.40 \\
&8.09 \\
&1.88 \\
&5.99 \\
&7.19 \\
&32.90 \\
&63.50 \\
&36.72 \\
&49.81
\end{aligned}
}
\]