What least number should be subtracted from 642 so that the remainder when divided by 5, 7, and 9 will leave in each case the same remainder 4 ?  Pick:
A) 5  B) 6  C) 8  D) 9  E) 10
The LCM of 5, 7, and 9 is 315. The next multiple is  2*315= 
<gadget id="calculator"> 2*315</gadget>
<output>630</output>
630.   630 + {remainder}= 630 + 4= 
<gadget id="calculator">630 + 4</gadget>
<output>634</output>
634, which is 8 less than 642.   Answer: 8.
<result>C</result>
What least number should be subtracted from 642 so that the remainder when divided by 5, 7, and 9 will leave in each case the same remainder 4 ?