Patterns were mostly left out of the common-core math standards in the early grades (kindergarten and 1st grade) due to a lack of evidence that they helped children understand later math concepts.

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.

A Singapore math problem has gone viral, leaving many asking, "When is Cheryl's Birthday?" ABC News' Gio Benitez solves the puzzle in a step-by-step video guide.