There can be no number with an odd sum of 8 because 8 is not odd!
It may or it may not. Parity (whether the number is odd or even) has nothing to do with a sum of two odds being positive or negative. -5 + 3 = -2 is negative, while 5 + 3 = 8 is positive.
Well, honey, all you need to do is check the last digit of each number. If there's an odd number of odd digits, the sum is odd. If there's an even number of odd digits, the sum is even. So, in this case, 13 and 17 are odd, and 45 and 24 are even, which means the sum is odd without adding them all up. Easy peasy, lemon squeezy!
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"29" is the odd one out. because all the other nos. are in the Fibonacci series, and 29 is not. In the Fibonacci series, every number (except for the first two) is the sum of the previous two numbers.
There can be no number with an odd sum of 8 because 8 is not odd!
If you include 8 and 18 that is 11 numbers and their sum is 143 which is odd ---- Explanations (by the way, it is really not all the numbers between 8 and 18, it is just all the integers. There is an infinite number of numbers between 8 and 18, think of just 8, 8.1, 8.11, 8.111, 8.1111 etc) Here are some other fun ways to do this: One way to do it, of course is just to add 8+ 9 10 11 12 13 14 15 16 17 18 Before you add them all, consider just adding the last column, and looking at the ones column of that number. 8+9+0+1+2+....+8 that number is 53 so the sum is odd. If that numbers is even then the number is even OR Looking at just the odd numbers. The sum of even numbers is always even. An odd number and an even number is an odd number. So if the sum of the odd numbers is even then the last column will be an odd number and the total sum will be odd. The sum of odd numbers is even when there is an even number of them. Look at 2 odd numbers. (ie 3+3 =6, this is two odd numbers and their sum is even) 9,11,13,15,17 are even and there are 5 of them. This is an odd number of odd so the sum is odd. Now we know the sum of the odds and the evens is odd so the total of the last column must be odd and therefore the sum is odd. Another way is to see that the sum of the first n numbers is n(n+1)/2 We can add the sum of the first 18 numbers then subtract the sum of the first 7 numbers and what is left is the sum of the numbers 8 to 18. So in this case we have 18x19/2-8x9/2 which is (18x19-7x8)/2 this simplifies by first dividing the 18 and the 8 by 2 so we have 9x19-4x7= 171-28=143 OR What if we match up and add the 8 and the 18, the 9 and the 17, the 10 and the 16, the 11 and the 15, the 12 and the 14 and you have 13 left. This is the idea behind the formula for the first n numbers. That is 26x5+13=143
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the answer would be equal. For example 3+5=8 which is even.
The sum of two odd numbers is even and the sum of an even number and an odd number is odd.So the sum of three consecutive odd numbers is odd but 270 is even.Ergo there are no three consecutive odd numbers that sum to 270.Three consecutive numbers that sum to 270 are 89, 90, 91.Three consecutive even numbers that sum to 270 are 88, 90, 92.
10/21 First, observe that for the sum of the three balls to be odd, either one is odd and two are even, or all three are odd. Since the sum of two odd numbers is even, the sum of two even number is even, and the sum of an even number and an odd number is odd. P(exactly one is odd)=(5/9)*(4/8)*(3/7)*3=180/504=5/14 P(all three are odd)=(5/9)*(4/8)*(3/7)=60/504=5/42 P(sum is odd)=5/14+5/42=15/42+5/42=20/42=10/21, which is approximately .48
8
It may or it may not. Parity (whether the number is odd or even) has nothing to do with a sum of two odds being positive or negative. -5 + 3 = -2 is negative, while 5 + 3 = 8 is positive.
Well, honey, all you need to do is check the last digit of each number. If there's an odd number of odd digits, the sum is odd. If there's an even number of odd digits, the sum is even. So, in this case, 13 and 17 are odd, and 45 and 24 are even, which means the sum is odd without adding them all up. Easy peasy, lemon squeezy!
10
The sum of the first 1,000,000 positive even numbers is: 2 + 4 + 6 + 8 + ... + 2,000,000 The sum of the first 1,000,000 positive odd integers is: 1 + 3 + 5 + 7 + ... + 1,999,999 The difference between the two is: (2-1) + (4-3) + (6-5) + (8-7) + ... + (2,000,000-1,999,999). This is the same as: 1 + 1 + 1 + 1 + ... + 1. Well how many 1's are there? 1,000,000. So the difference is 1,000,000. Note that if the question asked for the difference between the sum of the first 1,000 positive even numbers and the sum of the first 1,000 positive odd numbers, the answer would be 1,000. The first n even numbers and odd numbers? n.
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