How many four-digit numbers that do not contain the digits 2, 3, 4, 5, 6, 7, or 8 are there? Choose the correct choice.
A) 30
B) 36
C) 42
D) 48
E) 54
The 1st digit can be filled up by the numbers: {1,9} = 2 ways   The 2nd digit can be filled up by the numbers: {0,1,9} = 3 ways   The 3rd digit can be filled up by the numbers: {0,1,9} = 3 ways   The 4th digit can be filled up by the numbers: {0,1,9} = 3 ways   The total number of such four-digit numbers is   2*3*3*3= 
<gadget id="calculator">  2*3*3*3</gadget>
<output>54</output>
54   The answer is 54.
<result>E</result>
How many four-digit numbers that do not contain the digits 2, 3, 4, 5, 6, 7, or 8 are there?