Tính nhanh

a, \(\frac{7}{13}\)x\(\frac{7}{15}\)-\(\frac{5}{12}\)x\(\frac{21}{39}\)+\(\frac{49}{91}\)x\(\frac{8}{15}\)3

b,(\(\frac{12}{199}\)+\(\frac{23}{200}\)-\(\frac{34}{201}\)) x (\(\frac{1}{2}-\frac{1}{3}-\frac{1}{6}\))

1. tính nhanh

(\(\frac{1}{3}\)+\(\frac{12}{67}\)+\(\frac{13}{41}\)) - (\(\frac{79}{67}\)-\(\frac{28}{41}\))

2. tìm x

\(\frac{1}{2}\). x + \(\frac{2}{1.2.3}\)+ \(\frac{2}{2.3.4}\)+............+\(\frac{2}{98.99.100}\)

Tìm x :

a) \(\frac{-1}{4}\). (\(\frac{x}{4}\)+ \(\frac{-2}{7}\)+ \(\frac{2}{8}\)) = \(\frac{-1}{7}\)+ \(\frac{2}{14}\)

b) \(\frac{5-x}{12}\)+ \(\frac{5}{12}\)- \(\frac{1}{8}\)= \(\frac{3}{8}\)

c) \(\frac{-12}{25}\). (\(\frac{3}{4}\)- x + \(\frac{6}{11}\)) = 0.

Ai nhanh mình tick , mình rất gấp lắm rồi.

Bài 1 tìm x

a, x - \(\frac{x}{3}\)= \(\frac{3}{57}\): \(\frac{12}{19}\)

b, (x +\(\frac{1}{4}\)-\(\frac{1}{3}\)) : ( 2 + \(\frac{1}{6}\)- \(\frac{1}{4}\))= \(\frac{7}{46}\)

c, \(\frac{13}{15}\)- ( \(\frac{13}{21}\)+ x) . \(\frac{7}{12}\)= \(\frac{7}{10}\)

Làm chi tiết hộ mình nha

Bài 1: 

A=0,7 . \(2\frac{2}{3}\). 20 . 0,375 . \(\frac{5}{28}\)

B=( 9,75 .\(21\frac{3}{7}\) + \(\frac{39}{4}\). \(18\frac{4}{7}\)) 

Bài 2

a)(x + \(\frac{1}{2}\)) . (\(\frac{2}{3}\)- 2x ) = 0

b)\(\frac{2}{3}x-\frac{1}{2}x=\frac{5}{12}\)

c) x .\(3\frac{1}{4}+\left(-\frac{7}{6}\right).x-1\frac{2}{3}=\frac{5}{12}\)

d)\(5\frac{8}{17}:x+\left(\frac{-4}{17}\right):x+3\frac{1}{7}:17\frac{1}{3}\)= \(\frac{4}{11}\)

bài 1:thực hiện phép tính

a,\(\frac{65}{91}\)+\(\frac{-33}{55}\) b,\(\frac{36}{-84}\)+\(\frac{100}{450}\) c,\(\frac{3}{7}\)+\(\frac{1}{2}\)-\(\frac{-3}{70}\) d,\(\frac{3}{5}\)+\(\frac{-1}{25}\)-\(\frac{-35}{100}\)

bài 2:tìm x,bt

a,x-\(\frac{-1}{5}\)=\(\frac{7}{25}\) b,x+\(\frac{5}{11}\)=\(\frac{4}{-9}\) c,\(\frac{5}{9}\)+\(\frac{x}{-1}\)=\(\frac{-1}{3}\) d,|x-4|=|\(\frac{-6}{7}\)|+\(\frac{3}{2}\)

bài 3:tính nhanh(hợp lí)

a,A=\(\frac{2}{15}\)+\(\frac{2}{35}\)+\(\frac{2}{63}\)+\(\frac{2}{99}\)+\(\frac{2}{143}\)

b,B=\(\frac{1}{21}\)+\(\frac{1}{77}\)+\(\frac{1}{165}\)+\(\frac{1}{285}\)

c,so sánh C=\(\frac{1}{11}\)+\(\frac{1}{12}\)+\(\frac{2}{12}\)+.................+\(\frac{1}{20}\)với \(\frac{1}{2}\)

mn giúp mk với ạ,mk đag cần gấp lắm,phải nộp luôn ạ,lm ơn

Câu 1 : Tính

a) \(\frac{2}{3}\)+\(\frac{1}{3}\)x ( \(\frac{-4}{9}\)+\(\frac{5}{6}\)) : \(\frac{7}{12}\)

b) S = \(\frac{1}{2}\)x \(\frac{1}{3}\)+\(\frac{1}{3}\)x\(\frac{1}{4}\)+\(\frac{1}{4}\)x\(\frac{1}{5}\)+\(\frac{1}{5}\)x\(\frac{1}{6}\)+\(\frac{1}{6}\)x\(\frac{1}{7}\)+\(\frac{1}{7}\)x\(\frac{1}{8}\)+\(\frac{1}{8}\)x\(\frac{1}{9}\)

c) A = \(\frac{5}{5.7}\)+\(\frac{5}{7.9}\)+...+\(\frac{5}{59.61}\)

d) M = \(\frac{3}{4}\)x\(\frac{8}{9}\)x\(\frac{15}{16}\)x\(\frac{24}{25}\)x...x\(\frac{99}{100}\)

e) N = \(\frac{1}{2}\)x\(\frac{-2}{3}\)x\(\frac{3}{4}\)x\(\frac{-4}{5}\)x\(\frac{5}{6}\)x\(\frac{-6}{7}\)x...x\(\frac{-98}{99}\)x\(\frac{99}{100}\)

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