HOUSTON (KTRK) -- A mental math system developed in the 1800's is helping some local students ace standardized tests and win math competitions. But the method isn't taught in most Houston schools.

Students in some local elementary schools are learning a completely different way of doing multiplication. It’s a technique that many parents can’t understand. It’s called lattice multiplication. The ...

The array method only works when one of the numbers being multiplied is bigger than 10. Look at both numbers and, where necessary, split into tens and ones. Draw out a rectangle. Label the top of the ...