# Math

Winnies friend marco guessed that her riddle was about the number 79 Why can't 79 be the answer to Winnies riddle

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Winnie wrote the following riddle:
I am a number between 60 and 100.
My ones digit is two less than my tens digit.
I am a prime number.

Part A
What number does Winnie’s riddle describe?
Explain.

Part B
Winnie’s friend Marco guessed that her riddle was about the number 79.
Why can’t 79 be the answer to Winnie’s riddle?
Explain.

Then:

Part A

The digit in the tens place must be 6, 7, 8, or 9.

So the number must be:

64
becouse oness digit 4 is two less than tens digit 6

75
becouse oness digit 5 is two less than tens digit 7

86
becouse oness digit 6 is two less than tens digit 8

and

97
becouse oness digit 7 is two less than tens digit 9

Since 64 and 86 are even, they are divisible by 2.

Since 75 has a 5 in the ones place it is divisible by 5.

So 64, 75, and 86 are not a prime numbers.

Since the only factors of 97 are 1 and 97, 97 is a prime number.

Part B

Although 79 is a prime number between 60 and 100, the ones digit is two more than the tens digit.

The ones digit should be two less than the tens digit.

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2. This helped me with my homework soooo much I'm studying for a test to so thanks for giving an explanation because now I get it and I will know how to do it on the test. Thank you for the help and also do you go to " Hawkins Elementary school" byyyyyyyeeeee. Also just because, HIT OR MISS!!!!!!!!!!!!!!

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3. The answers were the right one thank you

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4. tanks a lot I was struggling to help my sister o d this problem but you made it easy

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5. Oh my gosh, at first I was struggling with this problem and you made it a whole lot easier! Other websites didn't explain it so I'm very glad to see this! Good job and keep up the good work.

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6. I still don't get it how do you know the digits in the the tens place has to be 6, 7, 8, 9, ?

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7. I am trying to do a test!

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