A primary school classmate taught me this trick to remember the multiplication table of 9 (only works for 1x9 to 10x9):

1. Display your fingers in front of you. Like this -> \!!!/ \!!!/
2. For 1x9, close the 1st finger from the left. You should see 9 fingers after the closed one -> _|||/ \|||/
3. For 2x9, close the 2nd finger from the left. You should see 1 finger before the closed one, and 8 fingers after the closed one, which means 18. -> \_||/ \|||/
4. For 3x9, close the 3rd finger from the left. You should see 2 fingers before the closed one, and 7 fingers after the closed one, which means 27. -> \|_|/ \|||/
5. Continue the pattern for 4x9 up to 9x9.
6. For 10x9, close the last finger on the right. You should see 9 fingers before the closed one, and 0 fingers after the closed one, which means 90. -> \|||/ \|||_

Hope this helps. =)