Q&A for How to Teach a Child Addition

As soon as they can understand what they mean and focus. It depends on the child, but generally this would be in the age range of 2-4.

At first, we teach kids to add horizontally because it is much easier to figure out how to add the digits when solving horizontally. When children subtract/add horizontally they can see the problem play out better. But as they get older, teachers will instruct them on how to solve vertically in preparation for algebra and more advanced math.

Easy concepts like addition and subtraction are useful for using in the future. Literally everything uses the basic operations, which are addition and subtraction (learnt usually in kindergarten-second grade) and multiplication and division (usually learnt in third grade-fifth grade). You use addition and subtraction to count objects, to calculate averages of test scores, to calculate areas and perimeters of objects, etc. You use multiplication and division to calculate averages, and for more complicated concepts in school like algebra, geometry, calculus, (taught in middle school and high school) and for future jobs.

Fractions are too hard for kids in 1st grade. Instead, start teaching them double-digit addition/subtraction.