With all the aliens drawings in the previous pages, I went straight to "crop circles" ... which is obviously not the answer. We have the answer now, no worries, but I thought it was funny

Even my 8 years old daughter new the answer ...

I was stuck in this one for hours, and my 10 year old boy was the one that discover it ... hint: everything in the page helps, including the words written!

OK, ignore it, after reading carefully the hints, and putting the original long number (which I know by hard with nine digits, so it was easy for me to know that the riddle number is incorrect) and then comparing it digit by digit with the riddle number, you immediately find the answer ... best hint...

I am doing this book with my 8 and 10 years old kids, we really need help