B5:
a.
\(=\dfrac{\dfrac{16}{16}+\dfrac{8}{16}+\dfrac{4}{16}+\dfrac{2}{16}+\dfrac{1}{16}}{\dfrac{16}{16}+\dfrac{8}{16}+\dfrac{4}{16}+\dfrac{2}{16}+\dfrac{1}{16}}=\dfrac{\dfrac{16+8+4+2+1}{16}}{\dfrac{16+8+4+2+1}{16}}=\dfrac{\dfrac{31}{16}}{\dfrac{31}{16}}=1\)
b.
làm tương tự nha