I did not know this..

Dear Friends

 Awesome - I did not know this.

The letters 'a', 'b', 'c' & 'd'

           do not appear anywhere in the spellings of numbers 1 to 99

           (Letter 'd' comes for the first time in Hundred)

Letters 'a', 'b' & 'c' do not appear anywhere in the spellings of 1 to 999

           (Letter 'a' comes for the first time in Thousand)

   Letters 'b' & 'c' do not appear anywhere in the spellings of 1 to 999,999,999

           (Letter 'b' comes for the first time in Billion)

                                              and

Letter 'c' does not appear anywhere in the spellings of entire English Counting!