# What is the sum of the first 9 odd numbers?

The sum of the first nine odd numbers is 81.

### Sum of the first n odd integers?

Let's talk this out and see if we can work it out. The sum of the first N odd integers means, 1+3+5+7+9+11+... Where N is how many odd numbers we're adding. Let's choose numbers for N, and see if we can find a pattern. N=1 --> 1 (sum of the first odd integer) N=2 --> 1 + 3 = 4 (sum of the first 2 odd integers) N=3 --> 1 + 3 + 5 =…

### The sum of all numbers from 8 to 18 is an even number?

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…

### How we can select five numbers single time does it take to form 50 out of this numbers 1 3 5 7 9 11 13 15 17 19?

There is no way without playing silly games. Each of the numbers in the list is odd. The sum of five odd numbers must be odd and therefore, cannot be 50. There is no way without playing silly games. Each of the numbers in the list is odd. The sum of five odd numbers must be odd and therefore, cannot be 50. There is no way without playing silly games. Each of the numbers in…

### How can you tie 100 horses in nine places We have only Nine places to tie 100 horses and we have to do it equally with ODD number?

You cannot without playing some silly games which have nothing whatsoever to do with mathematics. The sum of 9 odd numbers must be odd and so cannot equal 100 - which is even. You cannot without playing some silly games which have nothing whatsoever to do with mathematics. The sum of 9 odd numbers must be odd and so cannot equal 100 - which is even. You cannot without playing some silly games which have…

### Nine cards 1-9 are in a box and two cards are selected without replacement find probablity that both numbers selected are odd even though their sum is even?

Since the selected cards are not replaced, the selections are dependent. It is not given how many cards have an odd or even number. However, there are 2, 4, or 6 cards with an odd number, since the sum of all 9 card numbers is even. Let say that would be 4 cards with odd numbers, and 5 cards with even numbers. Then the probability that the first card selected with an odd number is…

### 9 odd numbers whose sum is 100?

ANSWER: There do not exist 9 odd numbers that will work Any odd number of odd number must be odd and 100 is even. Here is an easy way to see this. Take any odd number of odd numbers, say 9 of them. Now, pair them up by twos. so we have 4 pairs of two. Any two odd numbers will add up to an even number. But since we have an odd number of…

### If N is odd you add all odd numbers 1 to N and if N is even you add all even numbers 2 to N so according to this what is 2009 minus 2008 and how did you do that?

The formula for the sum of the odd number from 1 to N is N2 The sum of the even numbers form 2 to N is N(N+1) Here are examples of each to see how they work. Let's look at 1-5 The odd numbers are 1,3, an 5 and their sum is 9 which is the sum of the first THREE odd numbers so it is 32 The evens are 2,4 and their sum is…

### How many numbers are equal to the sum of two odd one-didit numbers?

You didn't state whether the two odd numbers to be added must be different odd numbers or whether they can be the same odd number. So I'll do both cases. Case 1: They can be the same odd number: They are all even numbers starting with 1+1=2 and ending up with 9+9=18. So you can get these 9 even numbers: 2,4,6,8,10,12,14,16,18. Case 2: They must be different odd numbers: If you require that the two…

### If two numbers are selected at random from the first five prime numbers What is the probability that their sum is an odd number?

There is a 40% chance that it will be an odd number. Explanation: The first five prime numbers are 2, 3, 5, 7, and 11. If one of the two numbers chosen is 2, the sum of the two numbers will be odd. 2 + 3 = 5 2 + 5 = 7 2 + 7 = 9 2 + 11= 13 But, if both numbers chosen are odd, the sum will be an even…

### There are nine pong balls numbered 1-9 in a bag If three balls are randomly selected without replacement what is the probability expressed as a common fraction that the sum of the number be odd?

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

### The sum of two odd numbers is an odd number?

No. 7 + 7 = 14 9 + 3 = 12 Odd + Odd = Even ------------------------------------------------------------- Now, I don't mean to disparage this answer. It's a perfectly good answer, I'm just posting a general proof. Let's write the sum in question as such: SUM from i=1 to i=2n OF (2i+1) Now, it can be proven with a little work that this is equal to 4n2+4n, or 4n(n+1). Because of the 4, the sum of…