A two-variable table is a table in which the value in each cell depends on two inputs: one at the head of the cell's column, and one at the beginning of the cell's row. A multiplication table is an example of a two-variable table.

Here's how to set up a mod-10 multiplication table in Excel.

1. Open a new worksheet and, if you like, change the column width to something useful, like 4. (Column width is under "Format".)

2. Type 0 in cell A2 and 1 in cell A3. Highlight both cells. There will be a small black box at the lower right corner of the highlighted region. Grab this with the mouse, and drag it down to cell A11. You should get the numbers 0 through 9 in column A.

3. Type 0 in cell B1 and 1 in cell C1. Highlight both cells. There will be a small black box at the lower right corner of the highlighted region. Grab this with the mouse, and drag it to the right, to cell K1. You should get the numbers 0 through 9 in row 1.

   	A	B	C	D	E	F	G	H	I	J	K
   1		0	1	2	3	4	5	6	7	8	9
   2	0
   3	1
   4	2
   5	3
   6	4
   7	5
   8	6
   9	7
   10	8
   11	9

4. Highlight cell B2. This is where you'll enter the formula. For this example, the formula is =mod($A2*B$1,10). The notation $A2 refers to the cell in column A and the current row (that is, row 2). The notation B$1 refers to the cell in row 1 and the current column.

5. To complete the formula, press "return." You should see a 0 in cell B2. Highlight this cell, grab the small box at the lower left corner, and drag it across to cell K2. This should fill row 2 with zeroes.

6. With this row still highlighted, grab the black box again, and drag it down to cell K11. This copies the formula through the table.

	A	B	C	D	E	F	G	H	I	J	K
1		0	1	2	3	4	5	6	7	8	9
2	0	0	0	0	0	0	0	0	0	0	0
3	1	0	1	2	3	4	5	6	7	8	9
4	2	0	2	4	6	8	0	2	4	6	8
5	3	0	3	6	9	2	5	8	1	4	7
6	4	0	4	8	2	6	0	4	8	2	6
7	5	0	5	0	5	0	5	0	5	0	5
8	6	0	6	2	8	4	0	6	2	8	4
9	7	0	7	4	1	8	5	2	9	6	3
10	8	0	8	6	4	2	0	8	6	4	2
11	9	0	9	8	7	6	5	4	3	2	1