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CEMC Gauss (Grade 7), 2023

Number theory Difficulty 1.5 Junior Find the answer Canada

The sum of two different prime numbers is 10. The product of
these two numbers is

Pick one

Solution

The prime numbers that are less than 10 are $2,3,5$ , and 7.

Thus, the only two different prime numbers whose sum is 10 are 3 and
7.

The product of these two numbers is $3\times7=21$ .

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