2x tables

0 x 2 = 2
1 x 2 = 2
2 x 2 = 4
3 x 2 = 6
4 x 2 = 8
5 x 2 = 10
6 x 2 = 12
7 x 2 = 14
8 x 2 = 16
9 x 2 = 18
10 x 2 = 20
11 x 2 = 22
12 x 2 = 24

As you can see, each time two is multiplyed by a number it will go up in twos.
Another way to explain it is the number two is being multiplyed by you will add that many twos on.
Example: 3 x 2 = 6
                2 + 2 + 2 = 6

See how we added three twos to make six? If it was eight that you wanted to multiply by two, for example, this would be how you'd do it:
Example 2: 8 x 2 = 16
                   2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 = 16

1x tables

1 x 1 = 1
1 x 2 = 2
1 x 3 = 3
1 x 4 = 4
1 x 5 = 5
1 x 6 = 6
1 x 7 = 7
1 x 8 = 8
1 x 9 = 9
1 x 10 = 10
1 x 11 = 11
1 x 12 = 12

As you can see, one multiplyed by any other number will equal the number one is multiplyed by.

0x tables

0 x 0 = 0
0 x 1 = 0
0 x 2 = 0
0 x 3 = 0
0 x 4 = 0
0 x 5 = 0
0 x 6 = 0
0 x 7 = 0
0 x 8 = 0
0 x 9 = 0
0 x 10 = 0
0 x 11 = 0

As you can see, everything you times by zero will equal zero.