Children (and adults) often have difficulty with 7 and 8 times tables. I'm not sure why, maybe because it is a prime number, I just don't know.
We are working on 7 times tables this week at home.
We have a times table chart hung up on the back of the toilet door and with a captive audience the kids can rote learn the tables, but not necessarily understand how it works.
Some helpful websites:
Snappy Maths
The School Run - a paid subscription.
Math Salamanders
Ed Place
Dr Mike's Math Games for Kids
Those who know how to think, need no teachers - Mahatma Gandhi.
Teach your child to think.
Mrs Hale.