tinh nhanh

70+50+30+50+26+97+3+74

=(70+30)+(50+50)+(97+3)+(74+26)

=100+100+100+100

=400

209-134

56+78=134

78+97=175

145-74=71

12+56-34+89=68-34+89=34+89=123

70+50+30+50+26+97+3+74=(70+30)+(50+50)+(26+74)+(97+3)=100+100+100+100=400

209-134=75

210-73=137

134 175 71 191

help

a: \(\dfrac{25}{26}=1-\dfrac{1}{26}\)

\(\dfrac{50}{51}=1-\dfrac{1}{51}\)

mà \(-\dfrac{1}{26}< -\dfrac{1}{51}\)

nên \(\dfrac{25}{26}< \dfrac{50}{51}\)

b: \(\dfrac{149}{157}=1-\dfrac{8}{157}\)

\(\dfrac{449}{457}=1-\dfrac{8}{457}\)

mà \(-\dfrac{8}{157}>-\dfrac{8}{457}\)

nên \(\dfrac{149}{157}>\dfrac{449}{457}\)

74×26+26×25+99×74

= 20025

Trả lời

74.26+26.25+99.74

=26.(74+25)+99.74

=26.99.99+74

=99.(26+74)

=99.100

=9900

\(74\times26+26\times25+99\times74\)

\(=26\left(74+25\right)+99\times74\)

\(=26\times99+99\times74\)

\(=99\times\left(26+74\right)\)

\(=99\times100\)

\(=9900\)

a. = 100

b. = 7200

c. =10000000

d. = 2500

thanks

Bạn nên trình bày cách làm ...

\(\frac{x+73}{27}+1+\frac{x+74}{26}+1=\frac{x+27}{73}+1+\frac{x+26}{74}+1\)

\(\frac{x+73+27}{27}+\frac{x+74+26}{26}=\frac{x+27+73}{73}+\frac{x+26+74}{74}\)

\(\frac{x+100}{27}+\frac{x+100}{26}=\frac{x+100}{73}+\frac{x+100}{74}\)

\(\left(x+100\right)\left(\frac{1}{27}+\frac{1}{26}-\frac{1}{73}-\frac{1}{74}\right)=0\)

mà \(\frac{1}{27}+\frac{1}{26}-\frac{1}{73}-\frac{1}{74}\ne0\)

\(\Rightarrow x+100=0\Rightarrow x=-100\)

A)-4100
B)944
C)0
D)1007
E)-87
F)-45

Bùi Anh Tuấn xuất sắc quá

\(...=15x\left(26+74\right)=15x100=1500\)

   15 x 26 + 15 x 74

= 15 x (26 + 74)

= 15 x 100

= 1500

(-26) + 148 + (-74) + (-86) + (-48) = -86

(-26) + 148 + (-74) + (-86) + (-48)

= (-26 - 74 - 48) + 148 - 86

= -148 + 148 - 86

= 0 - 86

= - 86