Addition Subtraction within20

Addition and Subtraction within 20
1. Math Learning System: For Elementary math
2. Stage One: Addition & Subtraction Within Twenty
3. Target Students: Grade One Elementary Students
4. Can practice on smartphones and tablets.
5. Practice scores can be saved for record.
6. Practice scores can be sent to teachers or parents.
7. The speed and accuracy of solving each question should reach above nation’s mid or high level before moving on
to the next stage.
The chapter for practice :
(1) Vertical Addition within 10
(2) Vertical Subtraction within 10
(3) Vertical Addition within 20
(4) Vertical Subtraction within 20
(5) Horizontal Addition within 10
(6) Horizontal Subtraction within 10
(7) Horizontal Addition within 20
(8) Horizontal Subtraction within 20