15 + 12 + 25 + 35 + 42 + 25 = ?
Rút gọn rồi tính:
b, 12/28 15/35 42/49 =
c, 16/36 30/54 24/56 =
d, 12/36 20/48 25/60 =
b: \(=\dfrac{3}{7}\cdot\dfrac{5}{7}\cdot\dfrac{6}{7}=\dfrac{90}{343}\)
c: \(=\dfrac{4}{9}\cdot\dfrac{5}{9}\cdot\dfrac{3}{7}=\dfrac{20}{189}\)
d: \(=\dfrac{1}{3}\cdot\dfrac{5}{12}\cdot\dfrac{5}{12}=\dfrac{25}{432}\)
tính nhanh
(15+21)+(25-15-35-21)
(25+51)+(42-25-53-51)
(15+21)+(25-15-35-21)
=15+21+25-15-35-21
=[15-15]+[21-21]+[35-15]
=0+0+20
=20
(25+51)+(42-25-53-51)
= 25+51+42-25-53-51
=[25-25]+[51-51]+[42-53]
=0+0+(-11)
=-11
1+1+1+1+1+1+1+11+1+121+12+12+12+1+2+42+42+25+35=?
1+1+1+1+1+1+1+11+1+121+12+12+12+1+2+42+42+25+35=323
a, 29 + 131 + 237 + 763 b, 65 + 327 + 15 + 73 c, 12+ 54:18 - 8
d.45.58+ 45.42 e) 35 . 34 + 35 . 26+ 40.35 f. 65 . 25 + 65 . 45+ 30.65
g) 750 : {32 – [ 22 + (5. 32 – 42)]} + 100 h) {630 : [16 + 3.(6 + 3. 4)]} – 1
i) 5871: [928 – ( 247- 82). 5] + 21750 k) 375 : {32 – [ 4 + (5. 32 – 42)]} – 14
g) (15 + 37) + (52 – 37 – 17) h) (38 – 42 +14) - (38 – 42 - 15) i) (27 + 65 ) + (346 - 27- 65) k) - (27 + 65) - (346 – 27 - 65) l) (42 – 69 + 17) - (42 + 17) m) 24. (16 - 5) – 16. (24 – 5 ) n) (-12). 47 – 12 . 52 + (-12) p) 51 . (69 - 25) – 69. (51 - 25) |
g) (15 + 37) + (52 – 37 – 17) = 15 + 37 + 52 – 37 – 17 = 15 + 52 – 17 = 50 h) (38 – 42 +14) - (38 – 42 - 15) = 38 – 42 +14 - 38 + 42 + 15 = 14 + 15 = 29 i) (27 + 65 ) + (346 - 27- 65) = 27 + 65 + 346 - 27- 65 = 346 k) - (27 + 65) - (346 – 27 - 65) = -27 - 65 - 346 + 27 + 65 = -346 l) (42 – 69 + 17) - (42 + 17) = 42 – 69 + 17 - 42 - 17 = – 69 m) 24. (16 - 5) – 16. (24 – 5 ) = 24. 16 - 24 . 5 - 16 . 24 + 16. 5 = - 24 . 5 + 16. 5 = -8 . 5 = -40 n) (-12). 47 – 12 . 52 + (-12) = -12 (47 - 52 + 1) = -12 . (-4) = 48 p) 51 . (69 - 25) – 69. (51 - 25) = 51 . 69 - 51 . 25 – 69. 51 + 69. 25 = - 51 . 25 + 69. 25 = (- 51+ 69).25 = 450 |
1) 42/35 - [ 33/14 . 21/22 - ( 54/25 : 27/25 - 7/10 )]
2) a) 5/21 . x/34 = 35/102 b) 15/x . 21/13 = 45/91
Ét o ét giúp mình với ạ><!!
1) 42/35 - [ 33/14 . 21/22 - ( 54/25 : 27/25 - 7/10 )]
= 42/35 - ( 9/4-13/10)
=42/35-19/20
=1/4
2) a) 5/21 . x/34 = 35/102
x/34=35/102 : 5/21
x/34=49/34
=> x=34
Vậy x=34
b) 15/x . 21/13 = 45/91
15/x=45/91 : 21/13
15/x=15/49
=> x=49
Vậy x=49
Tính nhanh
A = \(\dfrac{1}{2}\) + \(^{\dfrac{1}{3}}\) + \(\dfrac{1}{6}\) + \(\dfrac{1}{12}\) + \(\dfrac{1}{15}\) + \(\dfrac{1}{20}\) + \(\dfrac{1}{25}\) + \(\dfrac{1}{30}\) + \(\dfrac{1}{35}\) + \(\dfrac{1}{42}\) + \(\dfrac{1}{56}\) + \(\dfrac{1}{63}\)
Mình đang cần gấp , mong mn giúp mình với ạ
quy đòng r tính nha ra \(\dfrac{199}{33}\)
1,tính
a,-37+12-25
b,-50-25+(-13)
c,12-25-(-13)
d,10-35+(-12)-(-15)
tính giá trị của biểu thức :
a . ( -27 - 15 ) : (-6) + (-4)
b . (-3+9 ) . ( -7 ) : ( - 14 ) + (-12)
c . 25 - ( -7-8) . (-6) : 45 + 15
d . 15 . ( 25 - 35 ) + 35 . ( 15 - 25 )
( -27 - 15 ) : ( -6 ) + (-4 )
= -42 : 6 + 4
= -7 + 4
= -3
( -3 + 9 ) . ( -7 ) : ( -14 ) + ( -12 )
= 6 . 7 : ( -14 ) + ( -12 )
= 42 : ( -14 ) + ( -12 )
= -3 + ( -12 )
= -15
Hai câu cuối tự làm nha ! Mik mới làm mẫu hai cái cho đó
d . 15 . ( 25 - 35 ) + 35 . ( 15 - 25 )
= 15. 25 - 15. 35 + 35. 15 - 35.25
= 15. 25 - 35.25
= 25. ( 35 - 25 )
= 25 . 10
= 250
15.(25 - 35) + 35.(15 - 25)
= 15.25 - 15.35 + 35.15 - 35.25
= 15.25 - 35.25
= 25.(35 - 25)
= 25.10
= 250