First, look at the 49. The only factor pair is 7 x 7 (1 x 49 can’t be used as we’re told to use 2 to 12).
Now, the 42 divided by 7 is 6 so we can put the 6 in the bottom left.
Also, this uses 7 twice so we know the other numbers can only appear once.
Looking at 15 and 27, there’s only one common factor as 1 can’t be used so we can put 3 on the left of that row.
Now, 15 divided by 3 is 5 and 27 divided by 3 is 9. These numbers can be filled in at the top.
Looking at 22 and 24, there’s only one common factor as 1 can’t be used so we can put 2 at the top of that column.
Now, 22 divided 2 is 11 and 24 divided by 2 is 12. These numbers can be filled in on the left.
We know that you cannot place the 8 in the only space left at the side, because you would have to use 5 again to make 40. This space must be occupied by the 4, and the top spaces are the 8 and 10 above the 32 and 40 respectively.
This completes all of the outside numbers so we can now do all of the inside by doing the multiplications.