Question: Consider:

```
int[][] multD = new int[5][];
multD[0] = new int[10];

```

Is this how you create a two-dimensional array with 5 rows and 10 columns?

I saw this code online, but the syntax didn't make sense.

Answer: 
Try:

```
int[][] multD = new int[5][10];

```

Note that in your code only the first line of the 2D array is initialized to 0.
Line 2 to 5 don't even exist. If you try to print them you'll get `null` for everyone of them.
Try this way:

```
int a[][] = {{1,2}, {3,4}};

int b[] = {1, 2, 3, 4};

```