police sunglasses website-Calculations too much bad, keep teaching children after

1. dozen by dozen:
formulas: the head by head,supra tk purple, tail plus tail,police sunglasses website, tail by tail.
Example: 12 × 14 =?
solution: 1 × 1 = 1
2 +4 = 6
2 × 4 = 8
12 × 14 = 168
Note: a bit multiply, not to use the 0 digit placeholder.
2. head the same, complementary tail (tail sum equal to 10):
formulas: a first add 1 to the head by head, tail by tail.
Example: 23 × 27 =?
solution: 2 +1 = 3
2 × 3 = 6
3 × 7 = 21
23 × 27 = 621
Note: a bit multiply, not use the 0 digit placeholder.
3. the first multiplier complementary, the same as another multiplier:
formulas: a first add 1 to the head by head, tail by tail.
Example: 37 × 44 =?
solution: 3 +1 = 4
4 × 4 = 16
7 × 4 = 28
; 37 × 44 = 1628
Note: a bit multiply, not to use the 0 digit placeholder.
4. dozens of dozens of one by one:
formulas: the head by head, head plus head, tail by tail.
Example: 21 × 41 =?
solution: 2 × 4 = 8
2 +4 = 6
1 × 1 = 1
; 21 × 41 = 861
5.11 by any number:
formulas: the whereabouts of the fixed end to end, in the middle 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 beginning and end
11 × 23125 = 254375
Note: and over 10 to enter one.
6. dozen by any number:
formulas: the first is not the second multiplier fall trends,ray ban sizes, the first factor is multiplied by the second factor behind the bits of each number, plus the next digit, again falling.
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 10 to enter one.