Wet prepaid voucher

I did my laundry this morning, and I forgot I put the prepaid voucher I bought just yesterday in my trousers pocket. When I realised it was already half an hour in washing, and the trousers and the voucher were soaking wet! The precious little paper still have some numbers in it which I can make out (you really need some intelligent guess for that too), but there were two numbers which are badly damaged that even intelligent guesses wouldn't do.

The first reaction was to try a few numbers, and failed. After thinking aloud while trying to calm screaming Agastya (because mommy was ignoring him for quite a while now - salvaging the soaking wet vouchers from the pants, panickly try to punch some numbers, by now he's getting agitated), I called Coles (where I got the voucher from) to check if they would have the record. Unfortunately no, it's just an automated system thingy, anyway, no record. Argh! Then, what to do? The only thing left to do is to try the combinations. There are 9 digits and just 2 numbers, so the combination is.. Hmm.. I don't know, my brain can't think. But shouldn't be too much, compared to if I have to guess all 10 numbers, no?! Besides, the second number had a round top. So it cannot be 1,4,5 or 7. That ruled out some combinations already.

Turned out the first number was 7, and the second number was 3. Geeeeeeeez.. That took about half an hour! Oh, by this time Agastya was happy because I gave him a tub of yoghurt.