What conjecture can you make about the sum of the first 10 odd numbers?

The sum 10 first odd numbers are:

1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19

You can see that the unit part of the numbers repeat, but in the latter 5 numbers we have:

1 + 3 + 5 + 7 + 9 + (10 + 1) + (10 + 3) + (10 + 5) + (10 + 7) + (10 + 9)

Now, we can rearrange this as:

2*(1 + 3 + 5 + 7 + 9) + 5*10

2*(23) + 5*10

now, every number multiplied by a 2, is an even number, and 5*10 = 50 is also an even number.

Here we can see that the sum of the first 10 odd numbers is an even number, and because is an even number different than 2, it is not a prime number.

You can solve the multiplications and get:

2*23 + 5*10 = 46 + 50 = 96

none of the above.

for one of the equations to be used in the process, there has to be a term in the equation since squared is .

since there is only a term in the first equation, we cannot derive a from completing the square.

solving with completing the square