Start with first column

Keep subtracting 1 from each entry in the column until one of the entries is 1 then

i) Double the entries in the row the 1 is in

ii) Subtract one from each entry in the first column

Do this until you have two entries in the column that are 1 then

i) Double the entries in the rows the 1s are in

ii) Subtract one from each entry in the first column

Do this until all entries in the first column are 1 then

i) Subtract one from each entry in the first column

The frst column's entries are now all zeroes.

You can now repeat this procedure for the second and third columns as doubling zeroes will not change the number