Question

[Hoàng Thị Trâm]

Bài 1.

A=\(\frac{1}{1}\)x\(\frac{1}{2}\)x\(\frac{1}{2}\)x\(\frac{1}{3}\)x\(\frac{1}{3}\)x\(\frac{1}{4}\)x\(\frac{1}{4}\)x\(\frac{1}{5}\)x\(\frac{1}{5}\)x\(\frac{1}{6}\)

Bài 2.

B=\(\frac{1}{1x2}\)+\(\frac{1}{2x3}\)+\(\frac{1}{3x4}\)+\(\frac{1}{4x5}\)+\(\frac{1}{5x6}\)

Bài 3.

B=\(\frac{2}{1x2}\)+\(\frac{2}{2x3}\)+\(\frac{2}{3x4}\)+\(\frac{2}{4x5}\)+\(\frac{2}{5x6}\)

Bài 4.

C=\(\frac{2}{1x3}\)+\(\frac{2}{3x5}\)+\(\frac{2}{5x7}\)+\(\frac{2}{7x9}\)+\(\frac{2}{9x11}\)

Bài 5.

C=\(\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}+\frac{1}{42}+...+\frac{1}{90}+\frac{1}{110}\)

Bài 6.Tính bằng cách thuận tiện nhất.

a.(792,81 x 025 + 792,81 x 0,75) x (11 x 9 - 900 x 0,1 - 9).

b.\(\frac{7,2:2x57,2+2,86x2x64}{4+4+8+12+20+....+220}\)

c.\(\frac{2003x14+1998+2001x2002}{2002+2002x503+504x2002}\)

d.\(\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}+\frac{1}{28}\)

đ.3,54 x 73 + 0,23 x 25 + 3,54 x 27 + 0,17 x 25

e.\(\frac{1}{3}+\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+\frac{1}{48}+\frac{1}{96}\)

g.\(\left(1-\frac{1}{2}\right)x\left(1-\frac{1}{3}\right)x\left(1-\frac{1}{4}\right)x\left(1-\frac{1}{5}\right)\)