速算练习 2.0

Quick Calculate
Gather speed calculation techniques commonly used to produce the corresponding topics
students can practice and see help for quick calculation process.
For example:
Head same, tail complement,Formulas: the head by head, tail plus tail, tail by tail.
Complement first , same digital another,Formulas: a first add 1 to the head by head, tail by tail.

QuickCalculate:
1 Select the type of exercise
2 Go to practice, enter the answer, or watching quick calculation process and help.
3.support comprehension practise.