Do you know that .........

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