K map or karnaugh's map is a very important topic when studying boolean algebra. Here is my powerpoint presentation to explain it in the easiest manner.Also I have added a question for your understanding.For the solution please write me up in the comment box.

2. INTRODUCTION
 A karnaugh map(k-map) is a graphical tool
to simplify boolean expression.It provides
an area to represent every row of the truth
table.
 This is perhaps the most extensively used
method for simplification of boolean
function as compare to other methods.
Cell = 2n ,where n is a number of variables

3. For the case of variables, we form a map
consisting of 22=4 cells as shown in 2 Figure .
BA
B
0 1
0
1
00 10
01 11
B
0 1
0
1
B
0 1
0
1
BA
BA AB
BA BA 
BA BA 
Maxterm Minterm
A

4.  3 variables Karnaugh map
AB
C 00 01 11 10
0
1
CBA CBA CAB CBA
CBA BCA ABC CBA
0 1 3 2
654 7
Cell = 23=8

5. 4 VARIABLE MAP
AB
CD 00 01 11 10
00
01
11
10
5
3
1
7
62
0 4
9
15
13
11
1014
12 8

6. Steps to solve expression using K-map
 Select K-map according to the number of variables.
 Identify minterms or maxterms as given in problem.
 For SOP put 1’s in blocks of K-map respective to the
minterms (0’s elsewhere).
 For POS put 0’s in blocks of K-map respective to the
maxterms(1’s elsewhere).
 Make rectangular groups containing total terms in
power of two like 2,4,8 ..(except 1) and try to cover as
many elements as you can in one group.
 From the groups made in step 5 find the product terms
and sum them up for SOP form.

7. RULES
• Groupings can contain only 1s; no 0s.
• Groups can be formed only at right angles;
diagonal groups are not allowed.
• The number of 1s in a group must be a power
of 2 – even if it contains a single 1.
• The groups must be made as large as
possible.
• Groups can overlap and wrap around the
sides of the Kmap.
• Use don’t care conditions when you can.

9. CONCLUSION
Kmaps provide an easy graphical method of
simplifying Boolean expressions.
A Kmap is a matrix consisting of the outputs of
the minterms of a Boolean function.
In this section, we have discussed 2- 3- and 4-
input Kmaps. This method can be extended to
any number of inputs through the use of
multiple tables.