Give me a short and simple method to find the sum of numbers from 63 to 87.?

Answer 1

You find the average of the 2 numbers and multiply by the number of numbers between and including 63 and 87.
The average is (87+63)/2=75. The number of numbers is
87-63+1=25 and 25x75=1875. Voila.

Answer 2

Ans 1875 Here goes, there are 25 numbers inclusive between 63 and 87.To achieve the total of numbers subtract the small from the larger and add one, 87-63=24+1=25. If the numbers were written in a column from 63 to 87 and then inversely in another column, then the pairs of numbers added..(63 + 87) ; (64 + 86) ... (86 + 64); (87 + 63) , the sum is 150. Since there are two columns of numbers divide by two..150/2 = 75. Multiply 75 x 25 and the total is 1875. As told to me by my ninth grade math teacher, a Swiss boy devised this method when his teacher confronted the class with the sum of the numbers between 1 and 100, some time ago in history. By the way the sum is 5050.

Answer 3

It depends what you mean by 'short and simple.' I'll tell you a way other than just adding up all the numbers, but I'm not sure how simple it will be for you.

The general principle is that you find the average number in the range, then multiply that by the number of occurrences (numbers) in the range.

So, to find the average: 87 + 63 = 150 / 2 = 75

Now,the number of numbers is the high number minus the bottom number, plus one. So 87-63=24 + 1 = 25.

You now know the average number between 87 and 63 is 75. And you know there are 25 numbers in the group. So you multiply 75 times 25, and the product is the sum of all the numbers, or 1,875.

Answer 4

I would solve it by summing the numbers from 1 to 87 and subtracting the sum of the numbers from 1 to 62.

The sum of 1 to n is n(n+1)/2.

So 87*88/2 - 62*63/2 = 1875 as others have posted

Answer 5

Equation to the sum of the series in AP is Sn = n(Mid-term), when `n' is an odd number. Here n= 25,
Therefore, Mid-term = (63 + 87 ) / 2 = 75
Accordingly, Sn = 25* 75= 1875.

Answer 6

87 - 63 = 24 so there are 25 numbers being added since you are including beginning and end points.

25 / 2 = 12.5

87 + 63 = 150
150 * 12.5 = 1875

equation is ((yy - xx + 1) / 2) times yy + xx where
yy = last number in series and
xx = first number in series

((87-63 + 1) /2) times 87 + 63
(25 /2) times 150
12.5 time 150
1875

Answer 7

(87+63)/2 * [(87-63)\2+1]

Answer 8

General formula:

(n^2 +2na -n)/2

where,
n = number of terms (consecutive integers)...in this example, 25 terms you want to add up
a = starting term (63 in this example).

By plugging in n=25 and a=63, you will get 1875.

Answer 9

first you subtract 63 from 87.
then multiply your answer by 63.
is'nt it simple, short and faster.

Answer 10

{(87*(87+1))/2}-{(62*(62+1))/2}