How many two-digit numbers that do not contain the digits 1 or 4 are there?	Choose the correct choice: A) 112 B) 56 C) 64 D) 49 E) 84
We can have 7 digits ( 2,3,5,6,7,8,9) for the first place ( tenth's place).   and similarly 8 digits for the unit digit. ( 0,2,3,5,6,7,8,9)   So in total 7*8= 
<gadget id="calculator">7*8</gadget>
<output>56</output>
56   Hence 56
<result>B</result>
How many two-digit numbers that do not contain the digits 1 or 4 are there?