a) \(79.2^3+21.2^3\)
\(=\left(79+21\right).2^3=100.8\)
= 800
b) \(2.\left(6.4^2-85:5\right)\)
\(=2.\left(96-17\right)=2.79\)
= 158
c) (- 5) . 8 . (- 2) . 3
= \(\left[\left(-5\right).\left(-2\right)\right].\left(8.3\right)\)
= 10 . 24 = 240
d) 200 + 32 - (50 + 32)
= 200 + 32 - 50 - 32 (quy tắc mở ngoặc đổi dấu)
= 200 + (32 - 32) - 50
= 200 - 50 = 150
e) 3 . \(\left(-2\right)^2\) + 4 . (- 5) + 20
= 3 . 4 + 4 .(- 5) + 20
= 4 . (-2) + 20
= - 8 + 20 = 12
Chúc học tốt!!
a) 79. 23 + 21 . 23
= 79 . 8 + 21 . 8
= ( 79 + 21 ) . 8
= 100 . 8
= 800
b) 2. ( 6 . 42 - 85 : 5 )
= 2 . ( 6 . 16 - 17 )
= 2 . ( 96 - 17 )
= 2 . 17
= 34
c) (-5) . 8 . (-2) . 30
= (-40) . (-2) . 3
= 80 . 3
= 240
d) 200 + 32 - ( 50 + 32 )
= 232 - 82
= 150
e) 3. (-2)2 + 4. (-5) + 20
= 3. (-4) + 4 . ( -5) + 20
= (-12 ) + (-20) + 20
= (-12) + 0
= (-12)
\(a,79.2^3+21.2^3.\)
\(=\left(79+21\right)2^3.\)
\(=100.2^3=100.8=800.\)
\(b,2\left(6.4^2-85:5\right).\)
\(=2\left(6.16-17\right).\)
\(=2\left(96-17\right).\)
\(=2.81=162.\)
\(c,\left(-5\right).8.\left(-2\right).3.\)
\(=\left[\left(-5\right).\left(-2\right)\right].\left(8.3\right).\)
\(=10.24=240.\)
\(d,200+32-\left(50+32\right).\)
\(=200+32-50-32.\)
\(=\left(200-50\right)+\left(32-32\right).\)
\(=150+0=150.\)
\(e,3.\left(-2\right)^2+4.\left(-5\right)+20.\)
\(=3.4+4.\left(-5\right)+20.\)
\(=\left[3+\left(-5\right)\right]4+20.\)
\(=\left(-2\right).4+20.\)
\(=\left(-8\right)+20=12.\)
~ Học tốt ~
a) 79.23+21.23
= (79+21).23
= 100.8=800
b) 2.(6.42-85 /5)
= 2.(6.16 -17)
=2.79
=158
c)(-5).8.(-2).3
= (-40).(-6)
= 240
d) 200+32 -(50+32)
= 232 - 82
=150
e) 3.(-2)2+4.(-5)+20
=3.4+(-20)+20
=12+0
=12
a) 79 . 23 + 21 . 23
= (79+21) . 23
= 100 . 8
= 800.
b) 2. ( 6 . 42 – 85 : 5)
= 2. ( 6 . 16 - 17)
= 2. ( 96 - 17)
= 2.79
= 158.
c) (-5) .8 . (-2) . 3
= (-5).(-2).8.3
= 5.2.8.3
= 10.24
= 240.
d) 200 +32 –( 50 +32 )
= 232 - 82
= 150.
e) 3 . (-2)2 + 4 . (-5) +20
= 3 . 4 + (-20) + 20.
= 12 + 0
= 12.
