Speed calculation, keep teaching children the futu
 

Reprinted from 416519890 at 18:40 on April 4th,cheap wedding dresses, 2010 Read (loading. ..) Comments (0) Category: Personal Diary
1. ten by ten:
formulas: the head by 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 multiply,christian audigier sale, not use the 0 digit placeholder.

2. head the same, complementary tail (tail add up to 10):
formulas: a first add 1 to the head by head,juicy couture purses, 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. complementary first multiplier, the same as the other multiplier:
formulas: a first add 1 to the head by head,juicy couture velour, tail by tail.
Example: 37 × 44 =?
solution: 3 +1 = 4
4 × 4 = 16
7 × 4 = 28
; 37 × 44 = 1628
Note: a bit multiply,juicy couture online, not use the 0 digit placeholder.

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

5.11 by any number:
formulas: sum of fixed fate, and 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 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,ed hardy uk, the first digit multiplied by the factor behind the second factor of each number, plus the next digit, again 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.


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