4000x3099

The product of 4000 and 3099 is 12,398,000.

To multiply two numbers, 4000 and 3099, you can use long multiplication. Here are the steps:

1. Write down the first number (4000) on the top line and the second number (3099) on the bottom line.
```
4000
×3099
------
```

2. Starting from the rightmost digit of the bottom number, multiply it with each digit of the top number, one by one.
```
4000
×3099
------
```

Multiply 9 (from 3099) with each digit of 4000 one by one:
```
4000
×3099
------
0
0
00
+36,000
```

3. Multiply 90 (from 3099) with each digit of 4000 one by one:
```
4000
×3099
------
0
0
00
+36,000
+360,000
```

4. Multiply 900 (from 3099) with each digit of 4000 one by one:
```
4000
×3099
------
0
0
00
+36,000
+360,000
+3,600,000
```

5. Multiply 3000 (from 3099) with each digit of 4000 one by one:
```
4000
×3099
------
0
0
00
+36,000
+360,000
+3,600,000
+12,000,000
```

6. Add up all the partial products to get the final result:
```
4000
×3099
------
=12,396,000
```

Therefore, the product of 4000 and 3099 is 12,396,000.