All you do mate, is look at the age of the horse and the weight on the horse etc and the more 10s you see after the horse's name, you just pick those ones.
http://www.grand-national-guide.co.uk/grand-national-runners.php I`m going for Weird Al for a £5..... Let my 3 kids choose 1 each too.....
You can thank me after the race! It is just whether you have picked the correct 10 year old or not! <disclaimer> this way is not a sure fire way to pick the winning horse, but history tells us that 10 year olds usually win the National, or at least that is what somebody said on the BBC 606 about 6 years ago. I think.
I'd like to see Roberto Goldback win it in the hope that the excitement will be too much for Nicky the Needle and he'll have a fatal heart attack live on TV. I'd pay good money to see that.