In this study, based on the validity of superconducting critical state model, two systems, one a superconducting system of multiple thin strips and the other SQUID (practically the system that includes vertical and horizontal superconductivity strips) are studied. The systems have been studied under free-bulk pinning assumption. The systems have placed in a perpendicular magnetic field which is increased gradually. We obtain the magnetic field and current density distributions by increasing the field in each step and we draw the magnetization curve of related systems. The comparison of magnetization curve shows that by raising the number of strips and displacing the strips, the geometrical barrier of systems increases and this barrier prevents the complete repulsion of magnetic flux of system. Therefore the magnetization become larger, the magnetic hysteresis increases and the additional kinks appear in the magnetization curve. The magnetic flux focusing and the role of gaps in exclusion of flux is obtained by calculating the so-called “effective area”. The effective area curves of the systems show that by raising the number of strips, the total flux passing through the slots increases. For low external magnetic field the slope of effective area is ascending and then is descending for the higher applied magnetic field. In conclusion the decrease of focusing effects is unfavorable for the SQUID. But we are interested in investigating the effective area with ascendant slope. We saw this feature just in central slit of systems with even strips. The comparison of systems shows that by raising the number of strips the passing flux from central gap increases.