Question

1, 2, 3, 10, ?, 9802
A) 99
B) 199
C) 299
D) 999

Answer 1

2  = 1²+1
3  = 2²-1
10= 3²+1

10²-1=99  
                      A) 99

Answer 2

Answer:

Option – A. The number that is missing is 99 .

Solution:

Whenever a series of missing number is given, initially check whether the pattern is based on the squares/cubes. Then check if basic operations (addition, subtraction, division, multiplication) satisfies. Here the alternative addition and subtraction of the squares of the consequent numbers in the series is the pattern.  

The given series follows the pattern shown below,

$1^{2}+1=1+1=2$

$2^{2}-1=4-1=3$

$3^{2}+1=9+1=10$

$10^{2}-1=100-1=99$

$99^{2}+1=9801+1=9802$

Therefore, the missing number is 99 .