



 
Hi Mike, Every integer with an even units digit is divisible by 2. Do you see why? Every integer with a units digit of 5 is divisible by 5. Do you see why? That leaves 1, 3, 7 and 9. Is there a prime number larger than 10 that has a units digit of 1? What about 3 and 7 and 9? Penny  


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