There are 12 even numbers between 2 and 24 inclusive.
The sum is 154.
155
The sum of the first n odd numbers is n squared. 25 x 25 = 625
The sum of the even numbers is (26 + 28 + ... + 100); The sum of the odd numbers is (25 + 27 + ... + 99) Their difference is: (26 + 28 + ... + 100) - (25 + 27 + ... + 99) = (26 - 25) + (28 - 27) + ... + (100 - 99) = 1 + 1 + ... + 1 There are (100 - 26) ÷ 2 + 1 = 38 terms above which are all 1; their sum is 38 x 1 = 38. So the difference of the sum of all even numbers and all odd numbers 25-100 is 38.
25 of them
There is no solution. You could do it if the numbers were odd: 25 and 27 are consecutive odd numbers that equal 52.
The sum of the first 25 prime numbers is 1,060.
155
The sum of the 25 primes less than 100 is even (it is 1060).The first prime number is 2. Every other prime number is odd.So, of the 25 primes less than 100, one is even and 24 are odd.Any two odd numbers sum to an even number. Therefore, an even number of odd numbers has an even sum. So the sum of 24 odd numbers is even.Therefore, the sum of the 25 primes less than 100 is even.
The sum of the first n positive integers (i.e. 1+2+3+...+n) is given by n(n+1)/2 so the sum of the first 25 positive integers is 1+2+3+...+25 = 25x26/2 = 325. The sum of the first 25 EVEN numbers will be double this i.e. 2+4+6+...+50 = 650.
The sum of the first 25 prime numbers is 1,060.
The sum of the first 25 numbers is 25*26/2 = 325 So the sum of the first 25 multiples of 12 is 325*12 = 3900
625
The sum of the first n odd numbers is n squared. 25 x 25 = 625
The sum of the even numbers is (26 + 28 + ... + 100); The sum of the odd numbers is (25 + 27 + ... + 99) Their difference is: (26 + 28 + ... + 100) - (25 + 27 + ... + 99) = (26 - 25) + (28 - 27) + ... + (100 - 99) = 1 + 1 + ... + 1 There are (100 - 26) ÷ 2 + 1 = 38 terms above which are all 1; their sum is 38 x 1 = 38. So the difference of the sum of all even numbers and all odd numbers 25-100 is 38.
By using the formula for an arithmetic series. This is basically obtained by reasoning: The sum of the first 25 numbers is the same as 25 multiplied by the average of those numbers; the average in this case is simply (1 + 25) / 2.
25 of them
If the sum of 2 numbers is 25 and their product is 156, the numbers are 12 and 13.