I like these lessons of multiplication and the extensions such as squaring numbers ending with 5, averaging, and with nos. with same first figures and second figures add up to 10. There are so many special cases for divisions too extending it into algebra. The areas of rectangles look easy now with less and easy steps. It is amazing to know the sutras such as by mere observation, spot the obvious, if one is in ratio the other is zero.
At this stage, I feel that I have learned a lot so far, I am starting to sink it now.