a, 15(21/43+22/43)=15.1=15

b, 399(45+55) / 1995(1996-1991)

=399.100 / 1995.5

=4

+/ \(\frac{16.25+44.100}{29.96+142.48}=\frac{16.25+4.11.100}{29.96+71.2.48}\)            +/\(\frac{1996.1995-996}{1000+1996.1994}=\frac{\left(1995+1\right).1995-996}{1000+1996\left(1995-1\right)}\)

\(=\frac{400+400.11}{29.96+71.96}=\frac{400\left(1+11\right)}{96\left(29.71\right)}\)                        \(=\frac{1995.1995+1995-996}{1000+1996.1995-1996}\)

\(=\frac{400.12}{96.2059}=\frac{50.96}{96.2059}=\frac{50}{2059}\)                              \(=\frac{1995\left(1995+1\right)-996}{1996.1995-996}=1\)

T i c k cho chị nha ^^ Lát chị làm tiếp cho giờ chị đi ăn cơm đã ^.<

\(\frac{1996.1995-996}{1000+1996.1994}=\frac{\left(1995+1\right).1995-996}{1996\left(1995-1\right)+1000}\)

\(=\frac{1995.1995+1995-996}{1996.1995-1996+1000}\)

\(=\frac{1995\left(1995+1\right)-996}{1995.1996-996}\)

\(=\frac{1995.1996-996}{1995.1996-996}=1\)

a) \(\frac{399\times45+55\times399}{1995\times1996-1991\times1995}=\frac{399\times\left(45+55\right)}{1995\times\left(1996-1991\right)}=\frac{399\times100}{1995\times5}=4\)

b) \(\frac{1996\times1995-996}{1000+1996\times1994}=\frac{1996\times\left(1994+1\right)-996}{1000+1996\times1994}=\frac{1996\times1994+1996-996}{1000+1996\times1994}\)

\(=\frac{1996\times1994+1000}{1000+1996\times1994}=1\)

c) \(\frac{637\times527-189}{526\times637+448}=\frac{637\times\left(526+1\right)-189}{526\times637+448}=\frac{637\times526+637-189}{526\times637+448}=\frac{637\times526+448}{526\times637+448}=1\)

d) \(\frac{677\times874+251}{678\times874-623}=\frac{677\times874+251}{874\times\left(677+1\right)-623}=\frac{677\times874+251}{874\times677+874-623}=\frac{677\times874+251}{874\times677+251}=1\)

Bạn "Nguyen bao ngoc" hôm qua đã ra câu hỏi này rồi và có người trả lời rồi nhé ! 

Link câu hỏi đây : https://olm.vn/hoi-dap/detail/240389573303.html 

a) 399 x 45 + 55 x 399

= 399 x (45 + 55)

= 399 x 100

= 39900

1995 x 1996 - 996

= 3982020 - 996

= 3981024

b) 1996 x 1995 - 996

= 3982020 - 996

= 3981024

1000 + 1996 x 1994

= 1000 + 3980024

= 3981024

c) 637 x 527 - 189

= 335699 - 189

= 335510

526 x 637 + 448

= 335062 + 448

= 335510

Lần sau dùng máy tính mà tính nhá !!!

a) 399 x 45 + 55 x 399 = 399 x (45 + 55) = 399 x 100 = 39900 1995 x 1996 - 996 = 3982020 - 996 = 3981024 b) 1996 x 1995 - 996 = 3982020 - 996 = 3981024 1000 + 1996 x 1994 = 1000 + 3980024 = 3981024 c) 637 x 527 - 189 = 335699 - 189 = 335510 526 x 637 + 448 = 335062 + 448 = 335510

a: \(399\cdot45+55\cdot399=399\cdot100=39900\)

\(1995\cdot1996-996=3981024\)

b: \(1996\cdot1995-996=3981024\)

\(1000+1996\cdot1994=3981024\)

câu 1

 16 x 25 + 44 x 100

 29 x 96 + 124 x 48

 16 x 25 +44 x 100

=400 + 4400

=4800

29 x 96 +124 x 48

=2784 + 5952

=8736

Vậy 4800

       8736             

Câu 1: 6 x 25 + 44 x 100 

 29 x 96 + 142 x 48

Giải :(6 x 25) + (44 x 100) = 

150 + 440 = 590

 (29 x 96) + (142 x 48) =

2784 + 6816 = 9600

Câu 2 :1994 x 1993 - 1992 x 1993

1992 x 1993 + 1994 x 7 + 1986

Giải : (1994 x 1993) - (1992 x 1993) =

3 974 042  - 3 970 056 = 3986

(1992 x 1993) + (1994 x 7) + 1986 =

 3 970 056 + 13 958 + 1986 = 3 986 000

Câu 3 :  399 x 45 + 55 x 399

 1995 x 1996 - 1991 x 1995

Câu 3 : 399 x 45 + 55 x 399

1995 x 1996 - 1991 x 1995

Giải : (399 x 45) + (55 x 399) 

15 255 + 21 945 = 37 200

(1995 x 1996) - (1991 x 1995) = 

3 982 020 - 3 972 045 = 9975

\(\frac{637\times527-189}{526\times637+448}\)

\(=\frac{637\times\left(526+1\right)-189}{526\times637+448}\)

\(=\frac{637\times526+637-189}{526\times637+448}\)

\(=\frac{637\times526+448}{526\times637+448}\)

\(=1\)

\(\frac{677\times874+251}{678\times874-623}\)

\(=\frac{677\times874+251}{\left(677+1\right)\times874-623}\)

\(=\frac{677\times874+251}{677\times874+874-623}\)

\(=\frac{677\times874+251}{677\times874+251}\)

\(=1\)

\(\frac{637\times527-189}{526\times637+448}\)

\(=\frac{526\times637+637-189}{526\times637+448}=\frac{526\times637+448}{526\times637+448}=1\)

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c) 637 x 527 - 189=335510  /  526 x 637 + 448=335510

d) 677 x 874 + 251 =591949 /  678 x 874 - 623=591949

học tốt

c, 637x527-189/526x637+448=335918,116

d, 677x874+251/678x874-623=91398,5605

\(\frac{677\times874+251}{678\times874-623}\)

\(=\frac{677\times874+251}{677\times874+874-623}=\frac{677\times874+251}{677\times874+251}\)

\(=1\)