Drawing boxes to solve problems.
A visual grid-based method for multiplying large numbers.
Introduced to Europe by Fibonacci in 1202.
Draw diagonals in your boxes and add down the slides.
In Plain English: Instead of carrying numbers in your head, the Lattice method lets you write every single number down in a grid box. You add along diagonal slides. It's great if you have messy handwriting.
In The Real World: Used often in computer algorithms to break down large math tasks.
Adding the numbers inside the box instead of the numbers on the outside.