Questions Related to maths

Multiple choice maths fun with numbers some special sequences triangular numbers properties and patterns of perfect squares

Observe the following pattern and fill in the missing number. 
$ \displaystyle 11^{2} =121$
$ \displaystyle 101^{2} =10201$
$ \displaystyle 10101^{2} =102030201$
$ \displaystyle 1010101^{2} =......................$

  1. $ \displaystyle 1010101^{2} $=10203030201

  2. $ \displaystyle 1010101^{2} $=10204040201

  3. $ \displaystyle 1010101^{2} $=1020304030201

  4. $ \displaystyle 1010101^{2} $=10204030201
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$11^{2}$$=$$121$

$101^{2}$$=$$10201$
$10101^{2}$$=$$10203020101$
$1010101^{2}$$=$$1020304030201$
$101010101^{2}$$=$$10203040504030201$
We will go up to number of  ones in the number numerically.
Hence, Option C is correct.

Multiple choice maths fun with numbers some special sequences triangular numbers properties and patterns of perfect squares

Find the sum of:
$1+3+5+7+9+11+13+15+17+19+21+23$

  1. $11^2$
  2. $12^2$
  3. $10^2$
  4. $13^2$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
$S _{n}=\dfrac{n}{2}\left [ 2a+(n-1)d \right ]$
$a =$ First term
$d =$ Common difference
$n =$ number of terms

Given series is an A.P.
with first term $=$ $1$
common difference $=$ $2$
and last term $=$ $23$

Sum $=$ $\dfrac{12}{2}$ $\times$ $(2+11\cdot 2)$ $=$ $12\times12$
Hence, Option B is correct.