\(A=-77.113+45.23+77.158\)

\(=-77.113+45.23-\left(-77\right).158\)

\(=-77\left(113-158\right)+45.23\)

\(=-77.\left(-45\right)+45.23\)

\(=-77.\left(-45\right)-\left(-45\right).23\)

\(=-45\left(-77-23\right)\)

\(=-45.\left(-100\right)\)

\(=4500\)

4500                                                                          

A= -77.113+45.23+77.158

A= 77.-113+45.23+77.158

A= 77(-113+158)+45.23

A= 77.45+45.23

A= 45(77+23)

A= 45.100

A= 4500

Ta có: \(-77\cdot113+45\cdot23+77\cdot158\)

\(=-77\left(113-158\right)+45\cdot23\)

\(=77\cdot45+23\cdot45\)

=4500

\(-77.113+45.23+77.158\)

\(=-77\left(113-158\right)+45.23\)

\(=-77.\left(-45\right)+45.23\)

\(=-45\left(-77-23\right)\)

\(=-45.\left(-100\right)\)

\(=4500\)

45,275

4,275                                                                                                                                                                nho cho minh nha cac ban

a. 45.34 + 45.37 + 71.23 + 33.71

= 45.(34 + 37) + 71.(23 + 33)

= 45.71 + 71.56

= 71.(45 + 56)

= 71 . 101

= 7171

a) \(45.34+45.37+71.23+33.71=45\left(34+37\right)+71\left(23+33\right)=45.71+71.56=71\left(45+56\right)=71.101=7171\)

b) \(23.46+23.52+98.35+98.42=23\left(46+52\right)+98\left(35+42\right)=23.98+98.77=98\left(23+77\right)=98.100=9800\)

c) \(27.34+27.56+90.20+26.90=27\left(34+56\right)+90\left(20+26\right)=27.90+90.46=90\left(27+46\right)=90.73=6570\)

d) \(12.37+12.78+115.29+115.59=12\left(37+78\right)+115\left(29+59\right)=115.12+115.88=115\left(12+88\right)=115.100=11500\)

b. 23.46 + 23.52 + 98.35 + 98.42

= 23.(46 + 52) + 98.(35+42)

= 23.98 + 98.77

= 98.(23 + 77)

= 98 . 100

= 9800

*S=1-1/4+1/4-1/7+1/7-1/11+1/11-1/14+1/14-1/17

S=1-1/17=16/17

*M=2(1/1.2+1/2.3+...+1/15.16)

M=2(1-1/2+1/2-1/3+..+1/15-1/16)

M=2(1-1/16)

M=2.15/16

M=15/8

:w

\(S=\frac{3}{1.4}+\frac{3}{4.7}+\frac{3}{7.11}+\frac{3}{11.14}+\frac{3}{14.17}\)

\(S=1-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{11}+\frac{1}{11}-\frac{1}{14}+\frac{1}{14}-\frac{1}{17}\)

\(S=1-\frac{1}{17}\)

\(S=\frac{16}{17}\)

\(M=\frac{2}{1.2}+\frac{2}{2.3}+\frac{2}{3.4}+...+\frac{2}{15.16}\)

\(M=2.\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{15}-\frac{1}{16}\right)\)

\(M=2.\left(1-\frac{1}{16}\right)\)

\(M=2.\frac{15}{16}\)

\(=\frac{30}{16}=\frac{15}{8}\)

d. 12.37 + 12.78 + 115.29 + 115.59

= 12 . ( 37 + 78 ) + 115 . ( 29 + 59 )

= 12 . 115 + 115 . 88

= ( 12 + 88 ) . 115

= 100 . 115

= 11 500

a. 45.34 + 45.37 + 71.23 + 33.71

= 45 . ( 34 + 37 ) + 71 . ( 23 + 33 )

= 45 . 71 + 71 . 56

= ( 45 + 56 ) . 71

= 101 . 71

= ( 100 + 1 ) . 71

= 7100 + 71

= 7171

a)=45.(34+37)+71(23+33)

=45.71+71.55

=71.(45+55)

=71.100

=7100

Phúc nè tui hỏi chơi thui đc ko? Nhưng mà tui Cần nó để làm một số chuyện

a'15.16.17-14.15.16+16.17.18-....-28.29.30

=>4A=28.29.30-14.15.16=21000=>a=7000

bc,làm tương tự

a.(a+1)=a(a+1)(a+2)---(a-1)a(a+1)

=a)12.(-13)+12.10

12.[(-13)+10]

12.(-3)

-36

b)(-25)+(-15)-(-21)+19

(-40)-2=(-42)

=a)12.(-13)+12.10

12.[(-13)+10]

12.(-3)

-36

b)(-25)+(-15)-(-21)+19

(-40)-2=(-42)

\(\frac{1}{99.100}-\frac{1}{98.99}-\frac{1}{97.98}-...-\frac{1}{15.16}\)

\(=\frac{1}{99.100}-\left(\frac{1}{15.16}+\frac{1}{16.17}+...+\frac{1}{97.98}+\frac{1}{98.99}\right)\)

\(=\frac{1}{9900}-\left(\frac{1}{15}-\frac{1}{16}+\frac{1}{16}-\frac{1}{17}+...+\frac{1}{97}-\frac{1}{98}+\frac{1}{98}-\frac{1}{99}\right)\)

\(=\frac{1}{9900}-\left(\frac{1}{15}-\frac{1}{99}\right)\)

\(=\frac{1}{9900}-\frac{28}{495}=-\frac{559}{9900}\)

=\(\frac{559}{9900}\)

k mk nha bn 

dù ko nhanh nhất nhưng 

mong bn ủng hộ mk nha!