Letters 'a', 'b', 'c' 'd' do not appear anywhere in the spellings of
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
Except C ..for...CASH !!