How many keystrokes are needed to type numbers from 1 to 100? Choose the correct answer: A) 192 B) 100 C) 90 D) 110 E) None of these
Explanatory Answer   While typing numbers from 1 to 100, there are 9 single digit numbers: from 1 to 9.   Each of these numbers requires one keystroke.   That is 9 key strokes.   There are 90 two-digit numbers: from 10 to 99.   Each of these numbers requires 2 keystrokes.   Therefore, 180 keystrokes to type the 2-digit numbers.   100 is a three-digit number which requires 3 keystrokes.   Totally, therefore, one requires   9 + 180 + 3= 
<gadget id="calculator">  9 + 180 + 3</gadget>
<output>192</output>
192 keystrokes.   Choice 192 is the correct answer.
<result>A</result>
How many keystrokes are needed to type numbers from 1 to 100?