The Most Squares per Sheet
Six squares on a page suit children who already know the method and want repetition to gain speed. The grids are drawn smaller than on the pages of one or four squares, yet every cell still takes a number written by hand, even a three-digit one.
Drills of Mental Math
Each square asks for a few subtractions from its total, which makes a page of six a compact drill: a handful of quick calculations per square, checked against the lines that cross. Timing a page, then trying to beat that time on the next one, keeps practice lively.
From Small Numbers to Large
The opening eight pages stay with the numbers 1 to 9 and a total of 15, a good way to learn the shape of the square. Later pages bring in numbers that reach 30, then 100, and the work moves from facts known by heart to sums and differences of two digits.