-5 + (-37 - 45 + 51) - (-37 + 51)

=  -5  - 37 - 45 + 51 + 37 - 51

=  - (5 + 45) - (37 - 37) + (51 - 51)

= - 50 - 0 + 0

= - 50

  - (15 - 47 + 58) + (15 - 47 ) + 3

= - 15 + 47 - 58 + 15 - 47 + 3

= (-15 + 15) + (47 - 47) - (58 - 3)

= 0 + 0 - 55

= - 55

  (53 - 45 - 49) - (53 + 45 - 49)

= 53 -  45 - 49 - 53 - 45 + 49

= (53 - 53) + (-49 + 49) - (45 + 45)

= 0 + 0 - 90

= - 90 

    13 - 15 + 49 - 13 + 15 - 48

=  (13 - 13) + (-15 + 15) + (49 - 48)

= 0 + 0 + 1

=  1 

15+13 -15-13 +49-48

a)

\( 49.(51 - 4) - 51.(49 + 4)\)

\(=49.51-49.4-51.49-51.4\)

\(=49.(51-4-51)-51.4\)

\(=49.(-4)-51.4\)

\(=4.(-49-51)\)

\(=4.(-100)\)

\(=-400\)

b)

\( 71.64 + 32.(-7) - 13.32\)

\(=71.32.2+32.(-7)-13.32\)

\(=142.32+32.(-7)-13.32\)

\(=32.(142-7-13)\)

\(=32.122\)

\(=3904\)

c)

\( 11 + (-13) + 15 + (-17) + ... + 59 + (-61)\)

\(=(-2)+(-2)+...+(-2)\)

\(=(-2).13\)

\(=-26\)

a. 49.51- 49.4 -51.49 -51.4

= -49.4 - 51.4

=4.(-49-51)

=4.-100

=-400

b.71.64 + 32.(-7) -13.32

= 71.64 + 32.(-7-13)

=71.64 + 32.-20 

=71.32.2 +32.-20

=32.(71x2-20)

=32. 122

= 3904

c. (11-13)+(15-17)+..+(59-61)

=-2 x 13

=-26

a) 193+556=749

b) 725-274=451

tk mn nha!

Đáp án :

a) 193 + 556 = 749

b) 725 - 274 =451

Học tốt

Giải ra tiht tiết cho mik cái

\(B=1.2.3+2.3.4+3.4.5+.......+49.50.51\)

\(\Rightarrow4B=1.2.3.4+2.3.4.4+3.4.5.4+.......+49.50.51.4\)

\(=1.2.3.4+2.3.4\left(5-1\right)+3.4.5\left(6-2\right)+.........+49.50.51.\left(52-48\right)\)

\(=1.2.3.4+2.3.4.5-1.2.3.4+3.4.5.6-2.3.4.5+.........+49.50.51.52-48.49.50.51\)

\(=49.50.51.52\)

\(\Rightarrow B=\frac{49.50.51.52}{4}=1624350\)

Tính hợp lí

a,15.(27+ 18 +6 ) + 15.( 23 +12)

  = 15(27+18+6+23+12)

  = 15.86

  = 1290

b,24.(15 + 49 ) + 12. ( 50 + 42 )

=12.2(15+49)+12.(50+42)

= 12(30+98)+12(50+42)

=12(30+98+50+42)

=12.220

= 2640

c,53.(51+4)+53.(49+96) +53

=53(51+4)+53(49+96)+53.1

=53(51+4+49+96+1)

=53.201

=10653

d,42.( 15 +96) +6.(25 +4).7  

=42(15+96)+42(25+4)

=42(15+96+25+4)

=42.140

=5880

tick đúng cho mk nha pikachu

20-2.(x+14)=16

Tính hợp lí:

\(a)\)\(15.\left(27+18+6\right)+15.\left(23+12\right)\)

\(=\)\(15.51+15.35\)

\(=\)\(15.\left(51+35\right)\)

\(=\)\(15.86\)

\(=\)\(1290\)

\(b)\)\(24.\left(15+49\right)+12.\left(50+42\right)\)

\(=\)\(24.64+12.92\)

\(=\)\(1536+1104\)

\(=\)\(2640\)

\(c)\)\(53.\left(51+4\right)+53.\left(49+96\right)+53\)

\(=\)\(53.55+53.145+53\)

\(=\)\(53.\left(145+55+1\right)\)

\(=\)\(53.201\)

\(=\)\(10653\)

\(d)\)\(42.\left(15+96\right)+6.\left(25+4\right).7\)

\(=\)\(42.\left(15+96\right)+42.\left(25+4\right)\)

\(=\)\(42.111+42.29\)

\(=\)\(42.140\)

\(=\)\(5880\)

1)69.24+69.120+144.31

= 69. (24+120) + 144.31

= 144.69 + 144.31

= 144. (69+31)

= 144.100

=14 400

2)95.103-95.2-95

= 95. (103-2-1)

= 95.100

= 9 500

4)47.62+31.106

= 47. 62+ (31.2). 53

= 47.62 + 62. 53

= 62. (47+53)

= 62.100

= 6 200

5) 54.12+27.77-27

= 27. (2.12) + 27.77 - 27.1

= 27. 24 + 27.77 - 27.1

= 27. (24+77-1)

= 27. 100

= 2 700

6) 49+215+51+83+85

= (49+51) + (215+85)+ 83

= 100 +300 + 83

= 483

a: \(=81\cdot51+49\cdot81=81\cdot100=8100\)

b: \(=371\left(65+25+10\right)=37100\)

a,81*51+49*153-49*72

= 81*51+49*(153-72)

=81*51+49*81

=81*(51+49)

=81*100

=8100

a) 128 + 43 + 72 + 57

= ( 128 + 72 ) + ( 43 + 57 )

= 200 + 100

= 300

b) 41 . 51 + 49 . 51

= 51 . ( 41 + 49 )

= 51 . 90

= 4590

= 

\(a,\) \(128+43+72+57\)

\(=\left(128+72\right)+\left(43+57\right)\)

\(=200+100\)

\(=300\)

\(b,\) \(41.51+49.51=51.\left(41+49\right)=51.90=4590\)

\(c,\) \(4^7:4^5=4^{7-5}=4^2=16\)

\(d,\) \(2.\left(5.4^2-18\right)\)

\(=2.\left(5.2^4-2.3^2\right)\)

\(=2.2.\left(5.2^3-3^2\right)\)

\(=4.\left(40-9\right)\)

\(=4.31=123\)

a) \(\text{13 x 58 x 4 + 32 x 26 x 2 + 52 x 10 }\)

\(\text{=(13 x 4 ) x 58 + 32 x 13 x 2 x 2 + 13 x 4 x 10}\)

\(\text{= ( 13 x 4 ) x 58 + 32 x ( 13 x 2 x 2 ) + ( 13 x 4 ) x 10 }\)

\(\text{= 52 x 58 + 32 x 52 + 52 x 10}\)

\(\text{=52 x ( 58 + 32 + 10 )}\)

\(\text{=52 x 100 = 5200}\)

b) \(\text{14 x 35 x 5 + 10 x 25 x 7 + 20 x 70 x 2}\)

\(\text{= ( 14 x 5 ) x 35 + (10 x 7 ) x 25 + 20 x 70 x 2 }\)

\(\text{= 70 x 35 + 70 x 25 + 20 x 2 x 70 }\)

\(\text{= 70 x ( 35 + 25 + 40 )}\)

\(\text{= 70 x 100 = 7000 }\)

e) \(\text{5.3.37.4+5.24.21+21.5.12}\)

\(\text{= 5.(3.37.4+24.21+21.12)}\)

\(\text{= 5.1200}\)

\(=6000\)

a) \(13.58.4+32.26.2+52.10\)

\(=52.58+32.52+52.10\)

\(=52.\left(58+32+10\right)\)

\(=52.100=5200\)

b) \(14.35.5+10.25.7+20.70\)

\(=7.5.35.2+10.7.25+20.70\)

\(=35.70+70.25+20.70\)

\(=70\left(35+25+20\right)\)

\(=70.80=5600\)

c) \(...=15\left(27+18+6+23+12\right)\)

\(=15\left(27+23+18+12+6\right)\)

\(=15\left(50+30+6\right)=15.86=1290\)

d) \(...=53\left(51+4+49+96+1\right)\)

\(=53\left(51+49+4+96+1\right)\)

\(=53\left(100+100+1\right)=53.201=10653\)

e) \(15.37.4+120.21+21.5.12\)

\(=15.4.37+60.2.21+21.60\)

\(=60.37+60.42+21.60\)

\(=60.\left(37+42+21\right)=60.100=6000\)