Math worksheet for subtracting 9-digit numbers, featuring 15 problems for students to solve.

The task involves subtracting 9-digit numbers from other 9-digit numbers. Below, I will solve each subtraction problem step by step and explain the process.

---

Problem 1:

$$
502879476 - 428400821
$$

#### Step-by-Step Solution:
1. Align the numbers by their place values:
$$
\begin{array}{r}
502879476 \\
- 428400821 \\
\hline
\end{array}
$$

2. Subtract digit by digit from right to left:
- Units place: \(6 - 1 = 5\)
- Tens place: \(7 - 2 = 5\)
- Hundreds place: \(4 - 8\) (borrow 1 from thousands place):
$$
14 - 8 = 6
$$
- Thousands place: \(3 - 0\) (after borrowing):
$$
2 - 0 = 2
$$
- Ten-thousands place: \(9 - 0 = 9\)
- Hundred-thousands place: \(8 - 4 = 4\)
- Millions place: \(2 - 8\) (borrow 1 from ten-millions place):
$$
12 - 8 = 4
$$
- Ten-millions place: \(0 - 2\) (after borrowing):
$$
9 - 2 = 7
$$
- Hundred-millions place: \(5 - 4 = 1\)

3. Combine the results:
$$
502879476 - 428400821 = 74478655
$$

---

Problem 2:

$$
679666274 - 667196908
$$

#### Step-by-Step Solution:
1. Align the numbers by their place values:
$$
\begin{array}{r}
679666274 \\
- 667196908 \\
\hline
\end{array}
$$

2. Subtract digit by digit from right to left:
- Units place: \(4 - 8\) (borrow 1 from tens place):
$$
14 - 8 = 6
$$
- Tens place: \(7 - 0\) (after borrowing):
$$
6 - 0 = 6
$$
- Hundreds place: \(2 - 9\) (borrow 1 from thousands place):
$$
12 - 9 = 3
$$
- Thousands place: \(6 - 9\) (borrow 1 from ten-thousands place):
$$
16 - 9 = 7
$$
- Ten-thousands place: \(6 - 6\) (after borrowing):
$$
5 - 6 \quad (\text{borrow 1 from hundred-thousands place})
$$
$$
15 - 6 = 9
$$
- Hundred-thousands place: \(9 - 1\) (after borrowing):
$$
8 - 1 = 7
$$
- Millions place: \(7 - 7 = 0\)
- Ten-millions place: \(6 - 6 = 0\)
- Hundred-millions place: \(6 - 6 = 0\)

3. Combine the results:
$$
679666274 - 667196908 = 12469366
$$

---

Problem 3:

$$
838434322 - 444914994
$$

#### Step-by-Step Solution:
1. Align the numbers by their place values:
$$
\begin{array}{r}
838434322 \\
- 444914994 \\
\hline
\end{array}
$$

2. Subtract digit by digit from right to left:
- Units place: \(2 - 4\) (borrow 1 from tens place):
$$
12 - 4 = 8
$$
- Tens place: \(2 - 9\) (borrow 1 from hundreds place):
$$
12 - 9 = 3
$$
- Hundreds place: \(3 - 9\) (borrow 1 from thousands place):
$$
13 - 9 = 4
$$
- Thousands place: \(3 - 9\) (borrow 1 from ten-thousands place):
$$
13 - 9 = 4
$$
- Ten-thousands place: \(4 - 4\) (after borrowing):
$$
3 - 4 \quad (\text{borrow 1 from hundred-thousands place})
$$
$$
13 - 4 = 9
$$
- Hundred-thousands place: \(8 - 1\) (after borrowing):
$$
7 - 1 = 6
$$
- Millions place: \(3 - 4\) (borrow 1 from ten-millions place):
$$
13 - 4 = 9
$$
- Ten-millions place: \(7 - 4\) (after borrowing):
$$
6 - 4 = 2
$$
- Hundred-millions place: \(8 - 4 = 4\)

3. Combine the results:
$$
838434322 - 444914994 = 393519328
$$

---

Problem 4:

$$
903778150 - 468530928
$$

#### Step-by-Step Solution:
1. Align the numbers by their place values:
$$
\begin{array}{r}
903778150 \\
- 468530928 \\
\hline
\end{array}
$$

2. Subtract digit by digit from right to left:
- Units place: \(0 - 8\) (borrow 1 from tens place):
$$
10 - 8 = 2
$$
- Tens place: \(5 - 2\) (after borrowing):
$$
4 - 2 = 2
$$
- Hundreds place: \(1 - 9\) (borrow 1 from thousands place):
$$
11 - 9 = 2
$$
- Thousands place: \(8 - 0\) (after borrowing):
$$
7 - 0 = 7
$$
- Ten-thousands place: \(7 - 3 = 4\)
- Hundred-thousands place: \(7 - 5 = 2\)
- Millions place: \(3 - 8\) (borrow 1 from ten-millions place):
$$
13 - 8 = 5
$$
- Ten-millions place: \(0 - 6\) (after borrowing):
$$
9 - 6 = 3
$$
- Hundred-millions place: \(8 - 4 = 4\)

3. Combine the results:
$$
903778150 - 468530928 = 435247222
$$

---

Problem 5:

$$
403400809 - 281375832
$$

#### Step-by-Step Solution:
1. Align the numbers by their place values:
$$
\begin{array}{r}
403400809 \\
- 281375832 \\
\hline
\end{array}
$$

2. Subtract digit by digit from right to left:
- Units place: \(9 - 2 = 7\)
- Tens place: \(0 - 3\) (borrow 1 from hundreds place):
$$
10 - 3 = 7
$$
- Hundreds place: \(8 - 8\) (after borrowing):
$$
7 - 8 \quad (\text{borrow 1 from thousands place})
$$
$$
17 - 8 = 9
$$
- Thousands place: \(0 - 5\) (after borrowing):
$$
9 - 5 = 4
$$
- Ten-thousands place: \(0 - 7\) (borrow 1 from hundred-thousands place):
$$
10 - 7 = 3
$$
- Hundred-thousands place: \(3 - 3\) (after borrowing):
$$
2 - 3 \quad (\text{borrow 1 from millions place})
$$
$$
12 - 3 = 9
$$
- Millions place: \(0 - 1\) (after borrowing):
$$
9 - 1 = 8
$$
- Ten-millions place: \(4 - 2 = 2\)

3. Combine the results:
$$
403400809 - 281375832 = 122024977
$$

---

Problem 6:

$$
268623255 - 210395979
$$

#### Step-by-Step Solution:
1. Align the numbers by their place values:
$$
\begin{array}{r}
268623255 \\
- 210395979 \\
\hline
\end{array}
$$

2. Subtract digit by digit from right to left:
- Units place: \(5 - 9\) (borrow 1 from tens place):
$$
15 - 9 = 6
$$
- Tens place: \(5 - 7\) (borrow 1 from hundreds place):
$$
15 - 7 = 8
$$
- Hundreds place: \(2 - 9\) (borrow 1 from thousands place):
$$
12 - 9 = 3
$$
- Thousands place: \(3 - 5\) (borrow 1 from ten-thousands place):
$$
13 - 5 = 8
$$
- Ten-thousands place: \(2 - 9\) (borrow 1 from hundred-thousands place):
$$
12 - 9 = 3
$$
- Hundred-thousands place: \(6 - 3\) (after borrowing):
$$
5 - 3 = 2
$$
- Millions place: \(8 - 0 = 8\)
- Ten-millions place: \(6 - 1 = 5\)
- Hundred-millions place: \(2 - 2 = 0\)

3. Combine the results:
$$
268623255 - 210395979 = 58227276
$$

---

Final Answers:

$$
\boxed{
\begin{aligned}
&74478655 \\
&12469366 \\
&393519328 \\
&435247222 \\
&122024977 \\
&58227276 \\
\end{aligned}
}
$$