A. 331+29+69 = 429 B. 29.8+50.2+31.8+37.41 = 149.21 C. 135+360+65+40 = 600 D. 63.28+63.82+37.69 = 164.79 E. 39.8+60.2+8.21 = 108.21 F .102-96+90-84+78-72+66-60+54-48 = -10 G. 99-97+95-93+91+89+....+7‐5+3-1 = 0 (Dãy số này có tính chất cộng gộp, vì từ số 99 đến số 7, các số chẵn và lẻ liên tiếp sẽ tương đương 0 khi cộng tổng)

a: =331+69+29

=400+29

=429

b; \(=8\left(29+31\right)+50\cdot2+37\cdot41\)

=8*60+100+1517

=580+1517

=2097

c: \(=135+65+360+40\)

=400+200

=600

d: \(=63\left(28+82\right)+37\cdot69\)

=63*110+37*69

=6930+2553

=9483

e: \(=8\left(39+21\right)+60\cdot2\)

=60*8+60*2

=60*10

=600

f: =102-72-96+66+90-60-84+54+78-48-72

=30-30+30-30+30-72

=30-72

=-42

g:

Sửa đề: 99-97+95-93+91-89+...+7-5+3-1

=(99-97)+(95-93)+(91-89)+...+(7-5)+(3-1)

=2+2+...+2+2

=2*50

=100

A. 331 + 29 + 69 = 429
B. 29.8 + 50.2 + 31.8 + 37.41 = 149.21
C. 135 + 360 + 65 + 40 = 600

D. 63.28 + 63.82 + 37.69 = 164.79
E. 39.8 + 60.2 + 8.21 = 108.21
F. 102 - 96 + 90 - 84 + 78 - 72 + 66 - 60 + 54 - 48 = 150
G. 99 - 97 + 95 - 93 + 91 + 89 + … + 7 - 5 + 3 - 1 = 50

a) 81 + 35 + 19 = (81 + 19) + 35

= 100 + 35

= 135

b) 78 + 65 + 135 + 22 = (78 + 22) + (65 + 135)

= 100 + 200

= 300

a) 81+35+19

=80+30+(1+9)+5

=110+10+5

=120+5

=125

b) 78+65+135+22

=70+60+130+20+(8+2)+(5+5)

=280+10+10

=300

a) 27/82 < 26/75 ( 2025/6250 < 2132\6250)

b) -49/78 > 64/ -95 ( - 3136/7410 > -4992/7410)

c) ta có: \(A=\frac{54.107-53}{53.107}=\frac{53.107+(107-53)}{53.107+54}=\frac{53.107+54}{53.107+54}=1\)

\(B=\frac{135.269-133}{134.269+135}=\frac{134.269+\left(269-133\right)}{134.269+135}=\frac{134.269+136}{134.269+135}>1\)

\(\Rightarrow A< B\)

d) ta có: \(A=\frac{3^{10}+1}{3^9+1}=\frac{3.\left(3^9+1\right)-2}{3^9+1}=\frac{3.\left(3^9+1\right)}{3^9+1}-\frac{2}{3^9+1}=3-\frac{2}{3^9+1}\)

\(B=\frac{3^9+1}{3^8+1}=\frac{3.\left(3^8+1\right)-2}{3^8+1}=\frac{3.\left(3^8+1\right)}{3^8+1}-\frac{2}{3^8+1}=3-\frac{2}{3^8+1}\)

mà \(\frac{2}{3^9+1}< \frac{2}{3^8+1}\Rightarrow3-\frac{2}{3^9+1}< 3-\frac{2}{3^8+1}\)

=> A < B

Cảm ơn Công chúa Ori nhìu nha

\(2569+354+78\)

\(=2923+78\)

\(=3001\)

\(2493-346+95\)

\(=2147+95\)

\(=2242\)

\(58+632-458\)

\(=690-458\)

\(=232\)

= 3001

= 2242

= 232

Học tốt!

2569+354+78=3001

2493-346+95=2242

58+632-458=232

a) \(\left(81+19\right)+35=135\)

b) \(\left(78+22\right)+\left(65+135\right)=100+200=300\)

c) \(\left(234+17716\right)+23=17950+23=17973\)

d) \(\left(99+1\right)+85=100+85=185\)

\(a,81+35+19=\left(81+19\right)+35=100+35=135\\ b,78+65+135+22=\left(78+22\right)+\left(65+135\right)=100+200=300\\ c,234+17716+23=\left(234+17716\right)+23=17950+23=17973\\ d,85+99+1=85+\left(99+1\right)=85+100=185\)

A) 81+ 19 +35

=100+35=135

B) 78+65+135+22

=78+22+65+135

100+200=300 

mấy câu cx làm tương tự

a = (81+19)+35

=100+35=135

b = (78+22)+(65+135)

=100+200=300

c = (234+17716)+23

=17950+23=17973

d = (99+1)+85

=100+85=185

a) 81 + 35 + 19 = (81 + 19) + 35 = 100 + 35 = 135

b) 78 + 65 + 135 + 22 = (78 + 22) + (135 + 65) = 100 + 200 = 300

c) 234 + 17716 + 23 = 17950 + 23 = 17973

d) 85 + 99 + 1 = 85+ (99 + 1) = 85 + 100 = 185

\(a,=116+19=135\\ b,=143+135+22\\ =278+22=300\\ c,=17950+23=17973\\ d,=184+1=185\)

53+87>0

-78-95<0

53+87>0

-78-95<0