Addition is such simple and profound concept that it seems unnecessary to write again about addition. However observation of many kids doing addition proves otherwise – at least 20% of kids do not understand the concept of “CARRYING” – the art of taking the excess (beyond 9) during addition, to the next column when adding right to left.
Take another look, when a kid is asked to add two numbers – very gracefully and with enthusiasm quickly adds the numbers. Trouble starts for them when asked ” Verify and show that your answers is correct”. Some students brave to subtract one of the addenda from the answer to see if the other addenda results. More so interesting is when the subtraction does not verify their answers. Now they do not know, if their addition was incorrect or the subtraction.
Most of the text books in the act of simplification, have separated the chapters on addition as (a) Simple addition and (b) Addition with Carrying. What has been lost in this seemingly innocous exercise is the REAL connection with the Place Value.
Lilavati of Bhaskaracharya, provided an elegant definition for addition - who can provide more elegant definition than Bhaskaracharya!! -
“Addition or Subtraction should be done Place-wise from right to left or vice-versa.”
This definition paves way for addition in any meaningful and self devised short cut (or speed) methods