68*35=2380

17*86=1462

175*42=7350

62*49=3038

53*29=1537

1023*29=29667

2075*23=47725

cái quái gì vậy

Tính hợp lý :

D, (-69)+(-14)+56-(-78)-(+97)-(-46) 

E, -35.(-14)+35.(-38)-35.46  

F, -86.42-42.(-18)+42.(-32

(135-35) . (-37) + 37 . (-42-58)

=100 . -37 + 37 . -100

=-3700 . -3700

=13690000

a) \(\dfrac{3}{35}+\dfrac{7}{20}+\dfrac{32}{35}+\dfrac{13}{20}\)

Áp dụng tính chất giao hoán, kết hợp của phép cộng, ta được:

\(\left(\dfrac{3}{35}+\dfrac{32}{35}\right)+\left(\dfrac{7}{20}+\dfrac{13}{20}\right)\)

\(=1+1\)

\(=2\)

b) \(\dfrac{18\cdot15\cdot56}{42\cdot27\cdot25}=\dfrac{2\cdot3\cdot3\cdot5\cdot3\cdot4\cdot2\cdot7}{2\cdot3\cdot2\cdot2\cdot3\cdot9\cdot5\cdot5}\)

\(=\dfrac{2\cdot2\cdot3\cdot3\cdot3\cdot4\cdot5\cdot7}{2\cdot2\cdot2\cdot3\cdot3\cdot5\cdot5\cdot9}=\dfrac{3\cdot2\cdot2\cdot7}{2\cdot5\cdot9}=\dfrac{42}{45}\)

\(\left\{5.\left[42:\left(5.3+50:10\right).3:2+4\right]\right\}+\left\{35.\left[63:9.\left(5^2\right)\right]\right\}\\ =\left\{5.\left[42:\left(15+5\right).1,5+4\right]\right\}+\left\{35.\left(9.25\right)\right\}\\ =\left\{5.\left[42:20.1,5+4\right]\right\}+\left\{35.225\right\}\\ =\left\{5.\left[2,1.1,5+4\right]\right\}+7875\\ =\left\{5.\left[3,15+4\right]\right\}+7875\\ =\left\{5.7,15\right\}+7875\\ =35,75+7875\\ =7910,75\)

{5.[42:(5.3+50:10).3:2+4]}+{35.[63:9.(52)]}={5.[42:(15+5).1,5+4]}+{35.(9.25)}={5.[42:20.1,5+4]}+{35.225}={5.[2,1.1,5+4]}+7875={5.[3,15+4]}+7875={5.7,15}+7875=35,75+7875=7910,75

{5.[42:(5.3+50:10).3:2+4]}+{35.[63:9.(52)]}

={5.[42:(15+5).1,5+4]}+{35.(9.25)}

={5.[42:20.1,5+4]}+{35.225}

={5.[2,1.1,5+4]}+7875={5.[3,15+4]}+7875

={5.7,15}+7875

=35,75+7875

=7910,75

a) -48 + (-35 + 19) - (32 + 45 + 21)

= -48 - 35 + 19 - 32 - 45 - 21

= (-48 - 32) - (35 + 45) + (19 - 21)

= -80 - 80 - 2

= -162

b) -47 + (38 - 13) - (-52 + 31 - 91)

= -47 + 38 - 13 + 52 - 31 + 91

= (-47 - 13) + (38 + 52) - 31

= -60 + 90 - 31

= 30 - 31 = -1

c) 54 + (-37) - (+70) + (-163) - (-246) + (-230

= 54 - 37 - 70 - 163 + 246 - 230

= (54 + 246) - (37 + 163) - (70 + 230)

= 300 - 200 - 300

= -200

còn lại tự lm

Tính hợp lý :

A, (-48)+(-35+19)-(32+45+21)

B, (-47)+(38-13)-(-52+31-91)

C, 54+(-37)-(+70)+(-163)-(-246)+(-230

0

(17+35-42+58-23-45):79=0

450 : 27 = 16.66666666666667

540 : 45 = 12

472 : 56 = 8.428571428571429

8192 : 64 = 128

4725 : 15 = 315

8058 : 34 = 237

5672 : 42 = 135.047619047619

1820 : 35 = 52

3388 : 49 = 69.14285714285714

3960 : 52 = 76.15384615384615

1800 : 75 = 24

450 : 27 = 16 dư 18

540 : 45 = 12

472 : 56 = 8 dư 24

8192 : 64 = 128

4725 : 15 = 315

8058 : 34 = 237

5672 : 42 = 135 dư 2

1820 : 35 = 52

3388 : 49 = 69 dư 7

3960 : 52 = 76 dư 8

1800 : 75 = 24

450;27=16,66666667

540:45=12

472:56=8,428571429

8192:64=128

4725:15=315

8058:34237

5672:42=135,047619

1820:35=52

3388:4969,14284714

3960:52=710,7692

1800:75=24

k mk nha