The grid that unlocks the universe.
Memorized products of single digit numbers.
In Victorian schools, reciting these was a daily ritual.
The 9s trick: The digits of the answer always add up to 9.
Plain English: These are the building blocks. You don't want to calculate 7 x 8 every time. You just want to KNOW it's 56. Memorizing this grid makes all future math faster.
Real-world example: Knowing how many eggs are in 3 cartons (3 x 12).
Thinking 7x8 is 54. It's the most common error! It's 56.