HARD
Earn 100

Here is fun with triangular numbers. First complete the list and then write them in the table as shown.

1, 3, 6, 10, _____ , _____ , _____ , 36, 45.

1 3 6 10       36  
  1 3 6 10       36
                 

Now add them together and write the sum in the bottom row.

What can you say about the numbers formed in this row?

Write your conclusion in the form of a statement.

Important Questions on Squares and Square Roots

MEDIUM

In the question given below, the numbers in the figures are related. Identify their relationships and find the missing numbers in the given figures.

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MEDIUM

Which number will replace the question mark?

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MEDIUM

In the question given below, the numbers in the figures are related. Identify their relationships and find the missing numbers in the given figures.

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HARD
Let E denote the set of all natural numbers n such that 3<n<100 and the set {1,2,3,,n} can be partitioned into 3 subsets with equal sums. Find the number of elements of E.
MEDIUM
A two-digit number is 4 times the sum of its digits. If 18 is added to the number, the digits are reversed. Find the number.
HARD
Let a and b be natural numbers such that 2a-b, a-2b and a+b are all distinct squares. What is the smallest possible value of b ?
EASY

Select the combination of letters that when sequentially placed in the blanks of the given series will complete the series.

l _ chtlgc _ tlg _ ht _ gc _ tlgch _

MEDIUM
The sum of the following series 1+6+912+22+327+1212+22+32+429+15(12+22++52)11+.... up to 15 terms, is:
EASY

If, in a two-digit number, the digit at unit place is x and the digit at tens place is 4, then the two-digit number is _____.

EASY
If in a certain way, 3  +  4  =  25 and 7  +  24  =  625, then 9  +  40  =  ?
EASY
If the sum of n terms of an AP is nR+12n(n-1)T,  where R and T are constants, then the common difference is
MEDIUM

Consider a three-digit number with the following properties:

I. If its digits in units place and tens place are interchanged, the number increases by 36
II. If its digits in units place and hundreds place are interchanged, the number decreases by 198 .

Now, suppose that the digits in tens place and hundreds place are interchanged. Then, the number

MEDIUM

Let ann=0 be a sequence such that a0=a1=0 and an+2=3an+1-2an+1,n0.

Then a25a23-2a25a22-2a23a24+4a22a24 is equal to

MEDIUM

In the question given below, the numbers in the figures are related. Identify their relationships and find the missing numbers in the given figures.

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MEDIUM

Let <an> be a sequence such that a1+a2+...+an=n2+3nn+1n+2. If 28k=1101ak=p1 p2 p3 ... pm, where p1, p2, ... pm are the first m prime numbers, then m is equal to

HARD
Let A1,A2,A3,.. be squares such that for each n1, the length of the side of An equals the length of diagonal of An+1. If the length of A1 is 12 cm, then the smallest value of n for which area of An is less than one, is
MEDIUM
The sum 1+13+231+2+13+23+331+2+3+...+13+23+33+...+1531+2+3+...+15-121+2+3+...+15 is equal to
MEDIUM

Which number will replace the question mark?

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HARD
The number of all 2-digit numbers n such that n is equal to the sum of the square of digit in its tens place and the cube of the digit in units place is
MEDIUM
Consider the set A of natural numbers n whose units digit is non-zero, such that if this units digit is erased, then the resulting number divides n. If K is the number of elements in the set A, then