58 x 75 + 25 x 58 - 58 x 28
a, 35 x 34 + 35 x 38 + 65 x 75 + 45 x 65
b, 39 x 8 + 60 x 2 + 21 x 8
c, 58 x 75 + 58 x 50 - 58 + 25
d, 125 x 98 - 125 x 46 - 52 x 25
a.35 x 34 + 35 x 38 + 65 x 75 + 45 x 65
= 35 x (34 + 38) + 65 x 75 + 65 x 45
= 35 x 72 + 65 x (75+45)
= 35 x 72 + 65 x 120
= 35 x 72 + 65 x (72 + 48)
= 35 x 72 + 65 x 72 + 65 x 48
= (35+65) x 72 + 65 x 48
= 100 x 72 + 65 x 48
= 7200 + 3120
= 10320
b.39 x 8 + 60 x 2 + 21 x 8
=39 x 8 + 15 x 4 x 2 +21 x 8
= 39 x 8 + 15 x 8 + 21 x 8
=(39 + 15 + 21) x 8
= 75 x 8
= 600
c.58 x 75 + 58 x 50 - 58 + 25
= 58 x 75 + 58 x 50 - 58 x 1 + 25
= 58 x(75+50-1)+25
= 58 x 124 + 25
= 7192 + 25
= 7217
d.125 x 98 - 125 x 46 - 52 x 25
= 25 x 5 x 98 - 25 x 5 x 46 - 25 x 52
= 25 x 490 - 25 x 230 - 25 x 52
= 25 x (490 - 230 - 52)
= 25 x 208
= 5200
Tìm x
X + 7 = 36
19 + x = 58
X + 28 = 75
X + 7 = 36
X = 36 − 7
X = 29
19 + x = 58
X = 58 − 19
X = 39
X + 28 = 75
X = 75 − 28
X = 47
Tim x
50 -2 x ( x +1 )=20
Tinh nhanh
147+230+53+70
7*85+27*7-7*12
58*75+58*50-58*25
58 x 57 + 58 x 50-58 x 25
\(58\times57+58\times50-58\times25=58\times\left(57+50-25\right)=4756\)
58 × 57 + 58 × 50 - 58 × 25
= 58 × (57 + 50 - 25)
= 58 × 82
= 4756
58 x 57 + 58 x 50-58 x 25
= 3306 + 2900 - 1450
= 4756
tính 1 cách hợp lí
a.4 2x 46+42 x 52
b.(-75)+58+(-25)
c.(-4) x 5 x (-25)
a. 42 . 46 + 42 . 52
= 42 . (46+52)
= 16 . 98
= 1568
b. -75+58+(-25)
= [-75+(-25)]+58
= -100+58
= -42
c. -4 . 5 . (-25)
= [-4 . (-25)] . 5
= 100 . 5
= 500
Viết số thích hợp vào chỗ chấm :
a) 73 x 36 + 14 x 73 = ............ x ( 36 + 14 )
b) 58 x 23 - 23 x 58 = ............ x ( 58 - 28 )
Viết số thích hợp vào chỗ chấm :
a) 73 x 36 + 14 x 73 = ........... x ( 36 + 14 )
b) 58 x 23 - 23 x 58 = ............ x ( 58 - 28 )
Bạn ơi cần thì dùng máy tính
Tính hợp lý:
45-58+(-45)+(+58)-3
(-57)-(-12)+3-(-57)
-(-24)-(-30)+(-24)-30+8
-(-12)+(+19)-(+12)+8-19
47-(-53)+(-47)-(+53)
-(+28)+32-(-28)+(-34)
15-(+72)+(-15)+(+72)
20-(+46)+(-25)-(-46)
28-(-32)+(-28)-32+5
-75+(-49)+(+75)+49-12
Giúp e vs ạ
45-58+(-45)+(+58)-3=45-58-45+58-3=(45-45)+(58-58)-3=-3
(-57)-(-12)+3-(-57)=-57+12+3+57=(-57+57)+12+3=15
-(-24)-(-30)+(-24)-30+8=24+30-24-30+8=(24-24)+(30-30)+8=8
-(-12)+(+19)-(+12)+8-19=12+19-12+8-19=(12-12)+(19-19)+8=8
47-(-53)+(-47)-(+53)=47+53-47-53=(47-47)+(53-53)=0
-(+28)+32-(-28)+(-34)=-28+32+28-34=(-28+28)-(34-32)=-2
15-(+72)+(-15)+(+72)=15-72-15+72=(15-15)+(72-72)=0
20-(+46)+(-25)-(-46)=20-46-25+46=(20-25)+(46-46)=-5
28-(-32)+(-28)-32+5=28+32-28-32+5=(28-28)+(32-32)+5=5
-75+(-49)+(+75)+49-12=-75-49+75+49-12=(-75+75)+(49-49)-12=-12
\(...=45-58-45+58-3=-3\)
\(...=-57+12+3+57=15\)
\(...=24+30-24-30+8=8\)
\(...=12+19-12+8-19=8\)
\(...=47+53-47-53=0\)
\(...=-28+32+28-34=-2\)
\(...=15-72-15+72=0\)
\(...=20-46-25+46=-5\)
\(=...28+32-28-32+5=5\)
\(...=-75-49+75+49-12=-12\)
1)Thuc hien phep tinh(nhanh neu co the):
a)53-2÷100÷4+23×5
b)295-(31-22×5)2
c)58×75+58×50-28:25
d)[(-15)+(-21)]+(25-40)
2)Tim x, biet:
a)156-(x+61)=82
b)6x-302=23×5
c)x-[42+(-28)]=8
d)|x-3|=|5|+|-7|
♥
Cac ban giai nhanh hai bai nay ho minh nhe!♥