1. Addition by mental calculation of three digit numbers without regrouping 2. Addition by mental calculation of three digit and single digit numbers with regrouping from the ones' place 3. Addition by mental calculation of three digit and single digit numbers with regrouping from the ones' place (2) 4. Addition by mental calculation of three digit and single digit numbers with regrouping from the ones' place (3) 5. Addition by paper and pencil calculation of three digit and single digit numbers with regrouping from the ones' place 6. Addition by mental calculation of three digit and double digit numbers with regrouping from the ones' place (1) 7. Addition by mental calculation of three digit and double digit numbers with regrouping from the ones' place (2) 8. Addition by mental calculation of three digit and double digit numbers with regrouping from the ones' place (3) 9. Addition by paper and pencil calculation of three digit and double digit numbers with regrouping from the ones' place 10. Addition by mental calculation of three digit and double digit numbers with regrouping from the ten' place (1) 11. Addition by mental calculation of three digit and double digit numbers with regrouping from the ten' place (2) 12. Addition by paper and pencil calculation of three digit and double digit numbers with regrouping from the ten' place (3) 13. Addition by mental calculation of three digit and double digit numbers with regrouping from the one's and the ten' place (1) 14. Addition by mental calculation of three digit and double digit numbers with regrouping from the one's and the ten' place (2) 15. Addition by mental calculation of three digit and double digit numbers with regrouping from the one's and the ten' place (3) 16. Addition by paper and pencil calculation of three digit and double digit numbers with regrouping from the one's and the ten' place 17. Addition by mental calculation of three digit and double digit numbers with regrouping from the one's and the ten' place (1) 18. Addition by mental calculation of three digit and double digit numbers with regrouping from the one's and the ten' place (2) 19. Addition by mental calculation of three digit and double digit numbers with regrouping from the one's and the ten' place (3) 20. Addition by mental calculation of three digit and double digit numbers with regrouping from the one's and the ten' place 21. addition in various methods using mental calculation