Do you know?
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 in the spellings of entire English Counting.
