Problems should use the Courier font. Why? Every Courier font character uses the same amount of space. A comma is the same width as the number 5. This means that all of the numbers line up perfectly for carrying during addition and bringing the zero down in division.
His arithmetic skills are awesome but when presented with a math story problem, he falls apart, helpless. No matter how many times I suggest that he read the problem carefully. note down the givens. assign names to intermediate and final values. form equations. activate his Kumon engine (brain), he just can't get past the read_the_problem_carefully step.