The sum of all the digits of the integers from 18 to 21 inclusive is 24 (1 + 8 + 1 + 9 + 2 + 0 + 2 + 1 = 24). What is the sum E of all the digits of the integers from 0 to 99 inclusive?  Choose the correct choice from the following:	A) 450	B) 810	C) 900	D) 1000	E) 1100
We want the sum of the digits from 0 to 99, so I approximated:   0-9 -&gt;45-&gt; (9+0)*10/2   40-49 -&gt;85(13+4)*10/2   90-99 -&gt;135(18+9)*10/2   We can see at a glance that theweightgoes up as the numbers go up (meaning the difference between 85 and 45 is 40, while 135-85 is 50, this means that the second part of this sequence carries more weight for our result), so we know that the final answer has to be more than 850 (85*10) but close to it, and that's just E=900:the answer is 900.
<result>C</result>
The sum of all the digits of the integers from 18 to 21 inclusive is 24 (1 + 8 + 1 + 9 + 2 + 0 + 2 + 1 = 24). What is the sum E of all the digits of the integers from 0 to 99 inclusive?