Tính nhɑnh :
ɑ, (-4) . (+125) . (-25) . (-6) . (-8) ;
b, (-98) . (\(1-26\)) \(-\) 246 . 98.
Tính nhanh: (-4).(+125).(-25).(-6).(-8)
(–4) . (+125) . (–25) . (–6) . (–8)
= [(–4) . (–25)] . [(+125) . (–8)] . (–6)
= (4 . 25) . [–(125 . 8)] . (–6)
= 100 . (–1000) . (–6)
= 100 . 1000 . 6 = 600 000
Bài 1.2: Tính nhanh:
5+ 5 + 5 + 5+ 5 + 5 +5+ 5 + 5 +5
25 + 25 + 25 + 25 + 25 + 25 +25 + 25
45 + 45 + 45 + 45 + 15 + 15 + 15 + 15
2 + 4 + 6 + 8 + 10 + 12 + 14 + 16 + 18
125 + 125 + 125 + 125 - 25 - 25 - 25 - 25
5+ 5 + 5 + 5+ 5 + 5 +5+ 5 + 5 +5=5x10=50
25 + 25 + 25 + 25 + 25 + 25 +25 + 25=25x8=200
45 + 45 + 45 + 45 + 15 + 15 + 15 + 15=(45x4)+(15x4)=180+60=240
5+ 5 + 5 + 5+ 5 + 5 +5+ 5 + 5 +5
= 5 x 10
= 50
25 + 25 + 25 + 25 + 25 + 25 +25 + 25
= 25 x 8
= 200
45 + 45 + 45 + 45 + 15 + 15 + 15 + 15
= 45 x 4 + 15 x 4
= 180 + 60
= 240
2 + 4 + 6 + 8 + 10 + 12 + 14 + 16 + 18
= (2 + 18) + (4 + 16) + (8 + 12) + (6 + 14) + 10
= 20 + 20 + 20 + 20 + 10
= 20 x 4 + 10
= 80 + 10
= 90
125 + 125 + 125 + 125 - 25 - 25 - 25 - 25
= 4 x (125 - 25)
= 4 x 100
= 400
(Tick cho mk pls ^^)
8. Bỏ dấu ngoặc rồi tính:
a) ( 17 – 229) + ( 17 - 25 + 229) ; b) ( 125 – 679 + 145) – ( 125 – 679 )
9. Tìm x biết: a) 15 – ( 4 – x) = 6 ; b) - 30 + ( 25 – x) = - 1 ;
c) x – ( 12 – 25) = -8 ; d) ( x – 29 ) – ( 17 – 38 ) = - 9
10. Tìm số nguyên x biết: a) x – 5 = - 1 ; b) x + 30 = - 4; c) x – ( - 24) = 3 ; d) 22 – ( - x ) = 12; e) ( x + 5 ) + ( x – 9 ) = x + 2 ; f) ( 27 – x ) + ( 15 + x ) = x – 24 .
tính nhanh
(-4).(+125).(-25).(-6).(-8)
[(-4).(-25)].[(-8).125].(-6)
=100.(-1000).(-6)
=600000
1.TÍNH NHANH
a, (-4) . (+125).(-25) .(-6) . (-8)
= ((-4)x(-25))x(125x(-8))x(-6)
= 100 x -1000 x -6
= -100000 x -6
= -600000
=(-4).(-25).(-8).125.(-6)
= 100 . -1000 . (-6)
= -100000 . (-6)
=600000
Tính theo cách hợp lý phép : 25×6×4×8×125
25.6.4.8.125
=(25.4).(125.8).6
=100.1000.6
=100000.6
=600000
\(25\cdot6\cdot4\cdot8\cdot125\)
\(=25\cdot4\cdot6\cdot8\cdot125\)
\(=100\cdot6\cdot1000\)
\(=100000\cdot6\)
\(=600000\)
\(25\times6\times4\times8\times125=\left(25\times4\right)\times6\times\left(125\times8\right)\)
\(100\times6\times1000=600\times1000\)\(=600000\)
Tính nhanh :
a, (-4).(+125).(-25).(-8).(-6)
b, (-2).(+12).(-50)
c, (-25).(-26).(-4)
a, ( -4 ).125.( -25 ).( -8 ).( -6 )
= [ ( -4 ).( -25 ) ].[ 125.( -8 ) ].( -6 )
= 100.( -1000 ).( -6 )
= ( -100 000).( -6 )
= 600 000
b, ( -2 ).12.( -50 )
= [ ( -2 ).( -50 ) ].12
= 100.12 = 1200
c, ( -25 ).( - 26 ).( - 4 )
= [ ( -25 ).( -4 ) ].( - 26 )
= 100.( -26 ) = -2600
a) (-4) . 125 . (-25) . (-8) . (-6)
= (-4). (-25) . 125 . (-8) - (-6)
= 100 . (-1000) . (-6)
= -100000 . (-6)
=600000
b)(-2).12.(-50)
= (-2) . (-50) . 12
= 100 . 12
= 1200
tính nhanh
(-4).125.(-25).(-6).(-8)
(-98).(1-246)-246.98
(-4).3.(-125).(-8)
(-67).(1-301)-301.67
mong mọi người zúp nha
(-4).125.(-25).(-6).(-8)
=4.25.8.125.(-6)
=100.1000.(-6)
=-600000
(-4).3.(-125).(-8)
=4.3.125.(-8)
=12.(-1000)
=-12000
(-98).(1-246)-246.98
=98.(246-1)-246.98
=98.(246-1-246)
=98.(-1)
=-98
(-67).(1-301)-301.67
=67.(301-1)-301.67
=67.(301-1-301)
=67.(-1)
=-67
Chúc bn làm tốt hen!
tính nhanh:
(-4) . (+125) . (-25) .(-6). (-8)
(-98) . (1-126) -126 .98
a)\(\left(-4\right).125.\left(-25\right).\left(-6\right).\left(-8\right)\)
\(=\left[\left(-4\right)\cdot\left(-25\right)\right]\cdot\left[125\cdot\left(-8\right)\right]\cdot\left(-6\right)\)
\(=100\cdot\left(-1000\right)\cdot\left(-6\right)\)
\(=600000\)
b) \(\left(-98\right)\cdot\left(1-126\right)-126\cdot98\)
\(=\left(-98\right)\cdot1-\left(-98\right)\cdot126-126\cdot98\)
\(=\left(-98\right)+98\cdot126-126\cdot98\)
\(=\left(-98\right)\)