How many numbers between 0 and 1270 have a prime tens digit and a prime units digit?	Select.
A) 186	B) 192	C) 198	D) 204	E) 210
From 1-9 there are 4 prime numbers {2, 3, 5, 7}. The 10s and 1s of the number must be made with these numbers. The total number of combinations is  4*4= 
<gadget id="calculator"> 4*4</gadget>
<output>16</output>
16. Thus every set of 100 consecutive positive integers has 16 such numbers.   From 0 to 1200, there  16*12= 
<gadget id="calculator"> 16*12</gadget>
<output>192</output>
192 such numbers.   From 1201 to 1270, the 10s units can only use 3 numbers {2, 3, 5}. 3*4=12.   The total number is then  192+12= 
<gadget id="calculator"> 192+12</gadget>
<output>204</output>
204   The answer is 204.
<result>D</result>
How many numbers between 0 and 1270 have a prime tens digit and a prime units digit?