Mind It!

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

Courtesy : An email message passed on to me by Srinivas Sheshadri