How many keystrokes are needed to type numbers from 8 to 180? Options:  A) 360  B) 180  C) 325  D) 425  E) None of these
Explanatory Answer   While typing numbers from 8 to 180, there are 2 single digit numbers: 8 and 9.   Each of these numbers requires one keystroke.   That is 2 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.   There are 81 three-digit numbers: from 100 to 180.   Each of these numbers requires 3 keystrokes.   Therefore, 243 keystrokes to type the 3-digit numbers.   Totally, therefore, one requires   2 + 180 + 243= 
<gadget id="calculator">  2 + 180 + 243</gadget>
<output>425</output>
425 keystrokes.   Choice 425 is the correct answer.
<result>D</result>
How many keystrokes are needed to type numbers from 8 to 180?