EASY MULTIPLICATION: By using formula (a+b)(a-b)=a 2 -b 2 we can do easy multiplication. In this case we are using base numbers as 100,400,900,1600,2500,3600,4900,6400,8100,10000. We need to practice the the square numbers from 1 2 to atleast 50 2 . Base number:10 By using formula (a+b)(a-b)=a 2 -b 2 below table represent easy multiplication.Here only difficult thing is subtracting square numbers from square of base number (100).In fourth column we are subtracting squared numbers from a base number. 9x11 (10-1)(10+1) (10 2 -1 2 ) (100-1) 99 8x12 (10-2)(10+2) (10 2 -2 2 ) (100-4) 96 7x13 (10-3)(10+3) (10 2 -3 2 ) (100-9) 91 6x14 (10-4)(10+4) (10 2 -4 2 ) (100-16) 84 5x15 (10-5)(10+5) (10 2 -5 2 ) (100-25) 75 4x16 (10-6)(10+6) (10 2 -6 2 ) (100-36) 64 3x17 (10-7)(10+7) (10 2 -7 2 ) (100-49) 51 2x18 (10-8)(10+8) (10 2 -8 2 ) (100-64) 36 1x19 (10-9)(10+9) (10 2 -9 2 ) (100-