5、将下列二进制数转变成十进制数 1001B=__________ 1101B=__________

解  (1) (10)_{2}=1\times 2^{1}+0\times 2^{0}=(2)_{10}(2) (101)_{2}=1\times 2^{2}+0\times 2^{1}+1\times 2^{0}=(5)_{10}(3) (111)_{2}=1\times 2^{2}+1\times 2^{1}+1\times 2^{o}=(7)_{10}(4) (0111)_{2}=0\times 2^{3}+1\times 2^{2}+1\times 2^{1}+1\times 2^{\circ }=(7)_{10}(5) (1010)_{2}=1\times 2^{3}+0\times 2^{2}+1\times 2^{1}+0\times 2^{0}=(10)_{10}(6) (1111)_{2}=1\times 2^{3}+1\times 2^{2}+1\times 2^{1}+1\times 2^{\circ }=(15)_{10}(7) (10101)_{2}=1\times 2^{4}+0\times 2^{3}+1\times 2^{2}+0\times 2^{1}+1\times 2^{0}=(21)_{10}(8) (11010)_{2}=1\times 2^{4}+1\times 2^{3}+0\times 2^{2}+1\times 2^{1}+0\times 2^{0}=(26)_{10}