3
6 and 3
28
Decimal has ten different digits - 0 1 2 3 4 5 6 7 8 9 Binary only has two different digits - 0 1
3
6
675:929::123:___ SOLUTION : Sum Of Digits in 675 is 6+7+5 = 18 Sum Of Digits in 929 is 9+2+9 = 20 Therefore, difference between them is 2 Sum Of Digits in 123 is 1+2+3 = 6 and sum of digits in 242 is 2+4+2 is 8 Therefore, difference is same So, the answer is 242
9 - 3 = 6
89999996-80000006=9999990
6
The difference is 360.
120 There are 6 digits in total. The numbers with 3 digits, with all digits distinct from each other, are the permutations of the 6 digits taken 3 at a time, and therefore there are 6*5*4 = 120 of them.
NB 3,9,21,39,63. We note that #1;The difference between 3 & 9 = 6 #2 ;The difference between 9 & 21 = 12 ( 2 x 6) #3 ; The difference between 21 & 39 = 18 ( 3 x 6) #4 ; The difference between 39 & 63 = 24 ( 4 x 6) So it follows #5 ; The difference between 63 & X = ( 5 x 6 = 30 ) So 63 + 30 = 93 The answer !!!!!