study hard
There are two ways to solve this problem: You may notice that if you take away 100 from the series and add the smallest and largest number (1 + 99), you get 100. Then if add the next numbers in (2 + 98), you also get 100. Soon, you see a pattern. 3 + 97 = 100, 4 + 96 = 100 and so on. If you do this all the way to 50, you get 100, forty-nine time or 49*100 which 4900. You then add the 100 you took away earlier and add that to 4900 to get 5000. Lastly, because there is only one 50 in 1 to 100, it stays as 50 and you add that to 5000 to get the answer: 5050. The second way is to use the summation equation. This only works if you are starting from 1 and adding all the consecutive numbers to a certain number, say n. The equation is n(n+1)/2 where "n" is the final number in the series which in this case is 100. So 100(100+1)/2 = 100(101)/2 = 10100/2 = 5050.
104
There are 25 of them. Here's an easy way to find them:-- Write down all the numbers from 1 to 100.-- Cross out all the even numbers except '2'.-- Cross out all the numbers with digits that add up to a multiple of '3', except '3'.-- Cross out all the numbers that end in '5', except '5'.-- Cross out any others that can be divided evenly by any number other than '1' and themselves.-- The 25 remaining numbers are the primes you're looking for.I told you it was easy !
you could multiply 84 by 10 = 840 then multiply 84 by 2 = 168 add these two numbers = 1008
study hard
Doing it mentally, the easiest method is usually to pair the greatest with the least and add them up, then add the resultant numbers using the same method until you end up with the sum.
Do this the easy way- what is half of 100- it is 50. Half of 12- is 6, Add 50 and 6 to get your answer.
A percentage is another way of writing a fraction. Percent stands for "out of a hundred" or " /100" Example: 15% = 15/100 = 0,15
There are two ways to solve this problem: You may notice that if you take away 100 from the series and add the smallest and largest number (1 + 99), you get 100. Then if add the next numbers in (2 + 98), you also get 100. Soon, you see a pattern. 3 + 97 = 100, 4 + 96 = 100 and so on. If you do this all the way to 50, you get 100, forty-nine time or 49*100 which 4900. You then add the 100 you took away earlier and add that to 4900 to get 5000. Lastly, because there is only one 50 in 1 to 100, it stays as 50 and you add that to 5000 to get the answer: 5050. The second way is to use the summation equation. This only works if you are starting from 1 and adding all the consecutive numbers to a certain number, say n. The equation is n(n+1)/2 where "n" is the final number in the series which in this case is 100. So 100(100+1)/2 = 100(101)/2 = 10100/2 = 5050.
There are 25 of them. Here's an easy way to find them:-- Write down all the numbers from 1 to 100.-- Cross out all the even numbers except '2'.-- Cross out all the numbers with digits that add up to a multiple of '3', except '3'.-- Cross out all the numbers that end in '5', except '5'.-- Cross out any others that can be divided evenly by any number other than '1' and themselves.-- The 25 remaining numbers are the primes you're looking for.I told you it was easy !
you could multiply 84 by 10 = 840 then multiply 84 by 2 = 168 add these two numbers = 1008
The method know as The sieve of Eratosthenes is the easiest method. you simply write down all the numbers from 1 to 100 in rows of 10 and then you go through and you mark out all of the multiples of 2,3,4,5,6,7,8,9,10
Many people. It was Gauss, apparently, who demonstrated the method of reversing the sequence and adding it to the original term by term.
-99
It is possible to compute numbers larger than can be written using normal mathematics. There is an algorithm that is used to compute the decimal expansion of pi. It is easy to compute the sum of all the counting numbers from one to 100. Add the highest and lowest, and you will get 101. Add the next highest, 99, and the next lowest, two, and you will again get 101. If you continue in this way to compute the sums, you will have the sum 101, computed 50 times. Now compute the product of 50 and 101, and you will get 5050. This is the sum of all the counting numbers from one to 100.
If you add the first and the last number, you have a sum of 101. The second number from the left and the second number from the right will also add up to 101. If you continue in this way, you get 50 pairs of numbers, each of which has a sum of 101, so the final result is 50 x 101.