How to add a column from a file to another file

Question

I have a file with two columns as

1 1
2 3
3 4

and a file with one column as

6
7
9

I would like to add the

Answer 1

A pure bash solution can be:

exec 3

Infiles:

cat >onefile <twofile <

Output:

1 1 6
2 3 7
3 4 9