Number not enable on writable book data tag

Today, I use the clear Command for a writable book, for detect if it's written in my book : "1". The Command work perfectly for any word, but when I try with any numbers, that doesn't work.
maybe this is normal but it would be better if we could do

I thought the command work but she doesn't, that's all.

The command is :

/clear @a writable_book 0 0 {pages:[1]}

I really hope that was fixe because I really need this for one of my machine and If it's not a bug, I hope that will add for 1.8, thanks for reading.

PS : I'm sorry if I do some mistake, my english isn't really good because I'm french.