1+ 1=2 1+2=3 1+3=4 1+4=5 1+5=6 1+6=7 1+7=8 1+8=9 1+9= 10?

2+ 1=3 2+2=4 2+3=5 2+4=6 2+5=7 2+6=8 2+7=9 2+8= 10?

3+ 1=4 3+2=5 3+3=6 3+4=7 3+5=8 3+6=9 3+7= 10?

4+ 1=5 4+2=6 4+3=7 4+4=8 4+5=9 4+6= 10

5+ 1=6 5+2=7 5+3=8 5+4=9 5+5= 10?

6+ 1=7 6+2=8 6+3=9 6+4= 10?

7+ 1=8 7+2=9 7+3= 10

8+ 1=9 8+2= 10?

9+ 1= 10

The subtraction formula within 10:

9-9=0 9-8= 1 9-7=2 9-6=3 9-5=4 9-4=5 9-3=6 9-2=7 9- 1=8?

8-8=0 8-7= 1 8-6=2 8-5=3 8-4=4 8-3=5 8-2=6 8- 1=7?

7-7=0 7-6= 1 7-5=2 7-4=3 7-3=4 7-2=5 7- 1=6?

6-6=0 6-5= 1 6-4=2 6-3=3 6-2=4 6- 1=5?

5-5=0 5-4= 1 5-3=2 5-2= 1 5- 1=4?

4-4=0 4-3= 1 4-2=2 4- 1=3?

3-3=0 3-2= 1 3- 1=2?

2-2=0 2- 1= 1?

1- 1=0?

Extended data:

1, fast addition: the calculation method of fast addition of arbitrary numbers is very simple. As long as learners remember a general formula of quick addition, they can completely solve the quick addition method of counting any number of digits from high to low.

For example: (1), 67+48 = (6+5) ×10+(7-2) =15, (2) 758+496 = (7+5) ×

2. Fast Subtraction: The fast subtraction for calculating any number of digits is also a general formula for fast subtraction-"Standard subtraction (for the number of borrowed digits) plus or minus the previous digit" can completely solve the fast subtraction for calculating any number of digits from high to low.

For example: (1), 67-48 = (6-5) ×/kloc-0+(7+2) =19, (2), 758-496 = (7-5 )×/kloc-0.

3. Fast multiplication: The general formula of Wei's fast multiplication is AB× CD = (a+1)× C×100+B× D+the number of Wei's fast multiplication×10.

Fast calculation of evolution number |=(a-c)×d+(b+d- 10)×c,

Fast calculation of evolution number ‖=(a+b- 10)×c+(d-c)×a,

Quickly calculate the evolution number ⅲ= a×d-' b' (complement )× C. It is unique and unparalleled.

(1), using the first fast calculation method, the evolution number =(a-c)×d+(b+d- 10)×c, which is suitable for the fast calculation of multiplication with the same beginning and end of any two-digit number, such as 26×28, 47×48 and 87× 88.

(2) Using the second fast calculation method, the number of transitions =(a+b- 10)×c+(d-c)×a is suitable for the fast calculation of any two-digit multiplication in which the sum of two digits of one factor is close to "10" and the difference of two digits of another factor is close to "0", for example, 28×

(3) Using the third method to calculate the evolution number = a× d-'b' (complement )× c is suitable for the multiplication of any two-digit number.

References:

Baidu Encyclopedia-Mathematical Addition Table