Given A = (212312) and B = (3242).
We can multiply these matrices since the number of colums in A = number of rows in B
AB = ((2*3)+(1*4)(2*2)+(1*2)(2*3)+(3*4)(2*2)+(3*2)(1*3)+(2*4)(1*2)+(2*2))
AB = ((6+4)(4+2)(6+12)(4+6)(3+8)(2+4))
= (1061810116)