Use a K-map to find a minimum expression for F:

1. Three variables:

a) F(a,b,c) = m0 + m2 + m5 + m6

(b) F(d,e,f) = m0 + m1 + m2 + m4

(c) F(r,s,t) = rt' + r's' + r's

2. Four Variables:

(a) F(A,B,C,D) = BD + BCD + ABC + ABCD + BD

(b) F(a,b,c,d) = ?m(0,1,3,5,6,7,11,12,14) (This is a sum of minterms)

(c) F(a,b,c,d) = ?m(0,2,3,4,7,8,14)

(d) F(a,b,c,d) = ?m(1,2,4,15) + ?d(0,3,14) (The second summation is a sum of dont cares)