8th Class Mental Ability Inserting Missing Number

Inserting Missing Number

Category : 8th Class


Inserting Missing Number


Learning Objectives


  • Inserting the Missing Numbers


Inserting the Missing Numbers


In such type of questions, a figure, a set of figures or a matrix is given, each of which bears certain characters, and be it numbers, letters or a group of letters / numbers following a certain pattern. The candidate is required to decipher this pattern and accordingly find the missing character in the figure.


Example 1

(a) 5                                          (b) 6

(c) 8                                          (d) 9

(e) None of these

Answer: (d)

Explanation: The sum of numbers on right and centre subtracted from the number on the left gives the number at the bottom, i.e.

\[93-\left( 27+63 \right)=3;\text{ }79-\left( 38+37 \right)=4,\]

Similarly, \[67-\left( 16+42 \right)=9\]


  • Example 2

(a) 3                             (b) 8

(c) 10                                        (d) 14

(e) None of these

Answer: (c)

Explanation: Letter R is 18th in order of alphabetical series. So the product of vertically opposite numbers + 18 (R) = the sum of two horizontally opposite number, i.e.,

\[(28\times ~23)+18=173+489\]



Letter C is 3rd in order, so

\[(54~\times 15)+3=342+471\]



Similarly, letter D is 4th in order

\[(1\times ~11)+4=5+?\]


\[15=5+?\] or  \[5+?=15\]

So'           \[?=15-5=10\]



Commonly Asked Question


(a) 31                            (b) 229

(c) 234                          (d) 312

(e) None of these

Answer: (c)

Explanation: The number at the bottom is the product of two numbers at the top, i.e.,

\[13~\times 17=221\]

\[12\times ~19=228,\]

Similarly, \[13~\times 18=234\]


(a) 693                                      (b) 939

(c) 981                                      (d) 993

(e) None of these

Answer: (c)

Explanation: The squares of two numbers on the top placed side by side gives the number inside the bottom triangle, i.e.,

\[{{6}^{2}}\] and \[{{3}^{2}}=369\]

\[{{2}^{2}}\] and \[{{5}^{2}}=425,\]

Similarly, \[{{3}^{2}}\] and \[{{9}^{2}}=981.\]



Other Topics

Notes - Inserting Missing Number
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