A Child in grade 3 can easily do the maths operations of addition, subtraction, multiplication and division. Doing a junior Vedic Maths Program is absolutely comfortable once these concepts are clear.
Grade 6 onwards , students understand easily higher calculations like squares, roots, square roots, decimals and divisibility along with the four mathematical operations. Doing a Senior Vedic maths program would be easy for them to understand.
Once the learner knows the conventional methods , he/she can be trained to build upon the speed with Vedic Sutras.