The sum of the first 100 odd numbers is 10,000. There are 100 odd numbers between 1 and 199, and each pair from the start and end of the sequence (e.g. 1 and 199, 3 and 197, etc.) adds up to 200. Multiplying 50 times 200 equals 10,000.
Know MoreOdd numbers are defined by their parity, which is the property that makes every integer either even or odd. All odd numbers have a parity of 1, while all even numbers have a parity of 2. Any set of odd numbers can be found by using odd = {2k + 1 : k therefore Z}.
Learn more in ArithmeticA number is divisible by 9 if and only if the sum of its digits is divisible by 9. If a number is divisible by 9, it is also divisible by 3 because 9 is a dividend of 3.
Full Answer >Calculate the sum of an arithmetic sequence with the formula (n/2)(2a + (n-1)d). The sum is represented by the Greek letter sigma, while the variable a is the first value of the sequence, d is the difference between values in the sequence, and n is the number of terms in the series.
Full Answer >The formula for the arithmetic mean of a group of numbers is A = S/N, where S represents the sum of all the numbers in the group, and N represents the total number of items in the group. Finding the arithmetic mean is essentially the same as taking the average.
Full Answer >Integers with the same sign are added and the sum takes the sign of the integers, while integers with different signs are subtracted and the difference takes the sign of the number with the highest absolute value. The set of integers include all the counting numbers, zero and the negatives of the counting numbers.
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