Introduction - If you have any usage issues, please Google them yourself
Automatic title 20 or less the abdication subtraction, and the innovative design
1) can be automatically out of the question into the adder subject, such as: 3+ 8 =? , Or?+8 = 16 or 7+? = 12.
2) automatic multiplication, such as: 2* 5 =? Or?* 5 = 35 or 8*? = 32.
3) random current topic is the binary addition, multiplication, and abdication subtraction subject.