1. The Map Method
Truth table of fn is unique but fn can be in many different algebraic forms
Simplification by using boolean algebra is often difficult because we don’t know how to proceed
Map method or Karnaugh map (K_Map) is simple and straightforward method that produces minimum number of terms.

2. Two-Variable Map
A fn variable have 2n minterms (cells)

4. Three- Variable Map
Adjacent cells represent minterms that differs by only one variable. Therefore, adjacent cells are identical except for one variable that appears complemented in one cell and uncomplemented in the adjacent cell.
Example : F(x,y,x) = ∑ (2,3,4,5)

5. Another example : F(x,y,z) = ∑(3,4,6,7)

9. Four variable Map

22. Multilevel NAND circuits
To convert multilevel AND-OR to all NAND:
Convert all ANDs with AND-invert
Convert all ORs with invert-OR
Check the bubbles in diagrams if any of them is not compensated by another small circle along the same line insert an inverter(One input NAND) or complement the input literal

27. Implementing NOR circuits
To convert multilevel AND-OR to all NOR:
Convert all ORs with invert-OR
Convert all ANDs with invert-AND
Check the bubbles in diagrams if any of them is not compensated by another small circle along the same line insert an inverter(One input NOR) or complement the input literal