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.
A lot of effort goes in generating printable maths lessons for children of all ages. Equations have been a source of great confusion for most children and these can be easily learnt by solving the worksheet pages. The worksheets can also be prepared according to the needs of the child. The customised work papers can have a limited number of problems, a predicted font size and a topic of interest.