Speed ​​calculation, afterward education kid keep
 

1. ten by ten:
formulas: the pate along head, tail plus tail, tail by tail.
Example: 12 × 14 =?
solution: 1 × 1 = 1
2 +4 = 6
2 × 4 = 8
12 × 14 = 168
Note: a bit amplify, no use the 0 numeral placeholder.

2. head the same,Supra Indy NS Shoes, complementary tail (tail add up to 10):
formulas: a 1st multiplication 1 apt the head by head,Supra Pilot Shoes, tail by tail.
Example: 23 × 27 =?
Solution: 2 +1 = 3
2 × 3 = 6
3 × 7 = 21
23 × 27 = 621
Note: a bit multiply,Supra Bullet Shoes, not use the 0 digit placeholder.

3. complementary first multiplier, the same for the additional multiplier:
formulas: a first add 1 to the head by head,Women's Supra Skytop II, tail by tail.
Example: 37 × 44 =?
solution: 3 +1 = 4
4 × 4 = 16
7 × 4 = 28
; 37 × 44 = 1628
Note: a bit multiply, not use the 0 digit placeholder.

4. dozens of dozens of one by one:
formulas: head by head,Women's Supra Vaider Shoes, head plus head,Supra Shoes, tail by tail.
Example: 21 × 41 =?
solutions: 2 × 4 = 8
2 +4 = 6
1 × 1 = 1
; 21 × 41 = 861

5.11 by anyone number:
formulas: sum of fixed destiny, and the medium of the drop-down.
Example: 11 × 23125 =?
Solution: 2 +3 = 5
3 +1 = 4
1 +2 = 3
; 2 +5 = 7
2 and 5, respectively, in the sum of
11 × 23125 = 254375
Note: and over ten to get into one.

6. dozen by any number:
formulas: Second Take is not the first fate of several trends, the first digit multiplied by the element back the second ingredient of every number, plus the afterward digit, anew missing.
Example: 13 × 326 =?
solution: 13 bits is 3
3 × 3 +2 = 11
3 × 2 +6 = 12
; 3 × 6 = 18
13 × 326 = 4238
Note: and over ten to get into one.