Sum of First n Natural Numbers
Trending Questions
Which term of the A.P. 121, 117, 113 … is its first negative term?
[Hint: Find n for a_{n} < 0]
If $\frac{3+5+7+....n}{5+8+11+....10}=7$, then the value of $n$ is
$35$
$36$
$37$
$40$
Find the sum of first n even natural numbers.
Find the sum of the following APs.
(i) 2, 7, 12, …., to 10 terms
Find the sum of first $n$ odd natural numbers.
Fill in the blanks in the following table, given that a is the first term, d the common difference and a_{n} the n^{th} term of the A.P.
a 
d 
n 
a_{n} 

I 
7 
3 
8 
…... 
II 
− 18 
….. 
10 
0 
III 
….. 
− 3 
18 
− 5 
IV 
− 18.9 
2.5 
….. 
3.6 
V 
3.5 
0 
105 
….. 
Show that ${a}_{1},{a}_{2},\cdots ,{a}_{n}\cdots $ form an AP where ${a}_{n}$ is defined as below
${a}_{n}=3+4n$ . Also find the sum of the first $15$ terms in each case.
What does $R$ equal in Math?
The sum of the arithmetic sequence 5, 10, 15, 20 is
100
25
50
75
A staircase consists of 20 steps. The length and breadth of each step is 100 m and 12 m respectively. The height of the lowermost step is 12 m and the height of the subsequent step increases by 12 m. Find the volume in m3 of the concrete required to make the staircase.
5250
2520
5225
5520
 30
 20
 40
 60
(i) The cost of digging a well for the first metre is Rs 150 and rises by Rs 20 for each succeeding metre.
(ii) The amount of air present in the cylinder when a vacuum pump removes each time $\frac{1}{4}$ of their remaining in the cylinder.
Q
(i) 25, 50, 75, 100, ...; x = 1000
(ii) −1, −3, −5, −7, ...; x = −151
(iii) $5\frac{1}{2},11,16\frac{1}{2},22,...;x=550$
(iv) $1,\frac{21}{11},\frac{31}{11},\frac{41}{11},...,x=\frac{171}{11}$
Find the sum of all threedigit natural numbers, which are multiples of $11$.
The sum of three consecutive odd natural numbers is $111$. Find the numbers.
 3
 4
 1
 2
Find the sum of each arithmetic series
1). 38+35+32+......+2
Verify that each of the following is an AP and then write its next three terms.
0, 14, 12, 34, ⋯
(a) 100
(b) 210
(c) 400
(d) 420
In the $1908$Olympic Games, the Olympic marathon was lengthened from $40\mathrm{kilometers}$ to approximately $42\mathrm{kilometers}$. Of the following, which is closest to the increase in the distance of the Olympic marathon, in miles? ($1\mathrm{mile}$ is approximately $1.6\mathrm{kilometers}$).
$1.00$
$1.25$
$1.50$
$1.75$
 9
 10
 11
 12
How many terms of an AP 27, 24, 21, ... are required to get the sum as 0?
27
19
24
17
The other name for literal numbers is
The first term of an A.P. is 12, the last term is 8, the common difference is 2. Find the sum of the A.P.
20
16
22
18