Difference between combinational logic circuit and sequential logic circuit?

The main difference between sequential circuits and combinational circuits is that sequential circuits compute their output based on input and state, and that the state is updated based on a clock.

Combinational logic circuits implement Boolean functions, so they are functions only of their inputs, and are not based on clocks.

combinational =========================== sequencial
1.memory unit is not required =============1 it is require to store the past history
2.it is faster =================== 2. less compare to that one
3.easy to design ====== 3. comparatively garder
4.parallel adder ============== 4. serial adder