How many numbers between 0 and 1470 have a prime tens digit and a prime units digit?
Answers:	A) 228	B) 236	C) 244	D) 252	E) 260
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 1400, there  16*14= 
<gadget id="calculator"> 16*14</gadget>
<output>224</output>
224 such numbers.   From 1401 to 1470, the 10s units can only use 3 numbers {2, 3, 5}. 3*4=12.   The total number is then  224+12= 
<gadget id="calculator"> 224+12</gadget>
<output>236</output>
236   The answer is 236.
<result>B</result>
How many numbers between 0 and 1470 have a prime tens digit and a prime units digit?