Introduction to the course of mental arithmetic. Introduction to soroban.
  • What is mental arithmetic? Introduction to soroban. A direct count.
  • Direct addition and subtraction on soroban, +/-5
  • Direct score, +/- 6,7,8,9. Double-Digit numbers
Formulas of junior fellows.
  • The composition of the number five. Formulas of junior fellows. +/- 3,4.
  • Junior fellows. +/-2
  • Fixing formulas of junior fellows. Solving two-digit examples.
Formulas "senior fellows".
  • The composition of the number 10. Formulas of senior fellows. +9,8,7,6
  • Senior fellows +5,4,3,2,1
  • Senior fellows -9,8,7,6,5,4,3,2,1
A compound of the formula.
  • A compound of the formula.
The solution of examples with multi-digit numbers.
  • Fixing all formulas. Solving examples with two-digit and three-digit numbers.