1. dozen by dozen: ,
New GHD Professional Black Straighteners
 formulas: the head by head,
GHD Leopard Grain Straighteners, tail and tail, 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,
GHD NZ, complementary tail (tail amount equal to 10): 
 formulas: a first increase 1 to the pate 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 for variant 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 morsel amplify, no to use the 0 digit placeholder. 
 
 4. dozens of dozens of an at one: 
 formulas: the head by head, head plus head,
GHD Hair, 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 nailed end to end,
GHD Classic Styler Straighteners, 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,
GHD, in the beginning and end 
 11 × 23125 = 254375 
 Note: and over 10 to enter one. 
 
 6. dozen by whichever number: 
 formulas: Second Take the first namely not the whereabouts of several trends, the first factor of the second digit is multiplied by a factor backward 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.