24 x 32 - 43 + 58 x 78 - 98 x 123 = ?
1. x - 8 +32= 68
2. x +8+32=68
3. 98-x +34=43
4. 98+x-34=43
5. x :5:4=800
6. 18+x=384:8
7. (84,6-2 x x):3,02= 5,1
8. x x5= 120:6
9. (15x 24-x) :0,25= 100:0,25
1. \(x-8+32=68\)
\(x-8=68-32\)
\(x-8=36\)
\(x=36+8\)
\(x=44\)
_____
2. \(x+8+32=68\)
\(x+8=68-32\)
\(x+8=36\)
\(x=36-8\)
\(x=28\)
_____
3. \(98-x+34=43\)
\(98-x=43-34\)
\(98-x=9\)
\(x=98-9\)
\(x=89\)
_____
4. \(98+x-34=43\)
\(98+x=43+34\)
\(98+x=77\)
\(x=77-98\)
\(x=-21\)
_____
5. \(x:5:4=800\)
\(x:5=800.4\)
\(x:5=3200\)
\(x=3200.5\)
\(x=16000\)
_____
6. \(18+x=384:8\)
\(18+x=48\)
\(x=48-18\)
\(x=30\)
_____
7. \(\left(84,6-2\times x\right):3,02=5,1\)
\(84,6-2.x=5,1.3,02\)
\(84,6-2.x=15,402\)
\(2.x=84,6-15,402\)
\(2.x=69,198\)
\(x=69,198:2\)
\(x=34,599\)
_____
8. \(x\times5=120:6\)
\(x.5=20\)
\(x=20:5\)
\(x=4\)
_____
9. \(\left(15\times24-x\right):0,25=100:0,25\)
\(\left(15.24-x\right):0,25=400\)
\(15.24-x=400.0,25\)
\(15.24-x=100\)
\(360-x=100\)
\(x=360-100\)
\(x=260\)
1,x-8+32=68
=>x-8=68-32=36
=>x=36+8=42
2,x+8+32=68
=>x+8=68-32=36
=>x=36-8=28
3,98-x+34=43
=>98-x=43-34=9
=>x=98-9=89
4,98+x-34=43
=>98+x=43+34=77
=>x=77-98=-21
5,x:5:4=800
=>x:20=800
=>x=800x20=16000
6,18+x=384:8=48
=>x=48-18=30
7,(84,6-2x):3,02=5,1
=>84,6-2x=5,1x3,02=15,402
=>2x=84,6-15,402=69,198
=>x=69,198:2=34,599
8,5x=120:6=20
=>x=20:5=4
9,(15x24-x):0,25=100:0,25=400
=>360-x=400x0,25=100
=>x=360-100=260.
1. \(...\Rightarrow x+24=68\Rightarrow x=68-24=44\)
2. \(...\Rightarrow x+40=68\Rightarrow x=68-40=28\)
3. \(...\Rightarrow3^{2\left(8+x\right)}=9=3^2\Rightarrow2\left(8+x\right)=2\Rightarrow8+x=1\Rightarrow x=-7\)
4. \(...\Rightarrow3^{2\left(8+x\right)}=77\) (bạn xem lại đề)
5. \(...\Rightarrow x:5=800.4\Rightarrow x:5=3200\Rightarrow x=3200.5=16000\)
6. \(...\Rightarrow18+x=48\Rightarrow x=48-18=30\)
7. \(...\Rightarrow84,6-2x=5,1.3,02=15,402\Rightarrow2x=84,6-15,402\Rightarrow2x=69,198\Rightarrow x=34,599\)
8. \(...\Rightarrow5.x=20\Rightarrow x=20:5=4\)
9. \(\left(360-x\right):0,25=400\Rightarrow360-x=400.0,25=100\Rightarrow x=400-100=300\)
bài 1 : tính nhanh
a) 2 x 12 x 43 + 3 x 32 x 8 + 25 x 6 x4
b) 78 x 31 + 78 x 24 + 17 x 78 + 28 x 78
mn giúp mik nha
a) 2 x 12 x 43 + 3 x 32 x 8 + 25 x 6 x4
=(2 x12) x43+(3 x8) x32+(6 x4) x25
=24 x43+24 x32+ 24 x25
=24 x(43+32+25)
=24 x100
=2400
b) 78 x 31 + 78 x 24 + 17 x 78 + 28 x 78
=78x(31+24+17+28)
=78x100
=7800
78 x 31 + 78 x 24 + 17 x 78 +28 x 78 = 78 x ( 31 + 24 + 17 +28 ) =78 x 100 =7800 mình chỉ biết làm phần B thôi thông cảm cho mình nha
Tìm x, biết:
a) x – 8 + 32 = 68
b) x + 8 + 32 = 68
c) 98 - x + 34 = 43
d) 98 + x – 34 = 43
a)
x – 8 + 32 = 68
x – 8 = 68 – 32
x – 8 = 36
x = 36 + 8
x = 44
b)
x + 8 + 32 = 68
x + 8 = 68 – 32
x + 8 = 36
x = 36 – 8
x = 28
c)
98 – x + 34 = 43
98 – x = 43 – 34
98 – x = 9
x = 98 – 9
x = 89
d)
98 + x – 34 = 43
98 + x = 43 + 34
98 + x = 77
x = 98 – 77
x = 21
tick cho mink nhé!
tính nhanh
( 100 + 58 ) x 58 + ( 200 - 42 ) x 12
128 x72 + 14 x 256
157 x99 + 123 + 34
67 + 98 x 45 + 23
\(\left(100+58\right)\times58+\left(200-42\right)\times12\)
\(=158\times58+158\times12\)
\(=158\times\left(58+12\right)\)
\(=158\times70=11060\)
\(128\times72+14\times256\)
\(=128\times72+14\times2\times128\)
\(=128\times\left(72+28\right)\)
\(=128\times100=12800\)
\(157\times99+123+34\)
\(=157\times99+157\times1\)
\(=157\times\left(99+1\right)\)
\(=157\times100=15700\)
\(67+98\times45+23\)
\(=98\times45+90\)
\(=98\times45+45\times2\)
\(=45\times\left(98+2\right)\)
\(=45\times100=4500\)
Tính nhẩm:
8 x 3
8 x 5
8 x 1
8 x 8
8 x 7
8 x 9
8 x 4
8 x 10
8 x 2
2 x 8
8 x 6
6 x 8
Bài 2: Tìm số tự nhiên x, biết:
a) 100-7(x-5)=58 b) 12(x-1):3=43+23
c) 24+5x=75:73 d)5.(x-1)-206=24.4
e) 5(x-4)2-7=13 f) (x+1)+(x+2)+....+(x+30)=795
g) 2x+3 - 3.2x+1=32 h) 221-(3x+2)3=96
Mn bày e gấp
a: Ta có: \(100-7\left(x-5\right)=58\)
\(\Leftrightarrow7\left(x-5\right)=42\)
\(\Leftrightarrow x-5=6\)
hay x=11
b: Ta có: \(12\left(x-1\right):3=4^3+2^3\)
\(\Leftrightarrow12\left(x-1\right)=216\)
\(\Leftrightarrow x-1=18\)
hay x=19
2023 x 14 + 2023 x 83 +97
78 x 31 + 78 x 24 + 78 x 17 + 78 x 22 x 72
371 x 69 + 371 x 14 + 629 x 83
91 x 51 + 49 x 163 - 49 x 72
3 x 12 x 17 + 4 x 9 x 81 + 2 x 6 x 6
42 x 17 + 58 x 83 x 42 x 83 + 42 x 83 + 58 x 17
tính bằng cách hợp lý nhất
`@` `\text {Ans}`
`\downarrow`
`2023 \times 14 + 2023 \times 83+97`
`= 2023 \times (14+83) + 97`
`= 2023 \times 97 + 97`
`= 196231 +97`
`= 196328`
`78 \times 31+78 \times 24+78 \times 17+78 \times 22 \times 72`
`= 78 \times (31+24+17+22 \times 72)`
`= 78 \times (31+24+17+1584)`
`= 78 \times 1656`
`= 129168`
`371 \times 69+371 \times 14+629 \times 83`
`= 371 \times (69+14) + 629 \times 83`
`= 371 \times 83 + 629 \times 83`
`= 83 \times (371+629)`
`= 83 \times 1000`
`= 83000`
`91 \times 51+49 \times 163-49 \times 72`
`= 91 \times 51 + 49 \times (163-72)`
`= 91 \times 51+49 \times 91`
`= 91 \times (51+49)`
`= 91 \times 100`
`= 9100`
`3 \times 12 \times 17 + 4 \times 9 \times 81 + 2 \times 6 \times 6`
`= 9 \times 4 \times 17 + 4 \times 9 \times 81 + 4 \times 9 \times 2`
`= 9 \times 4 \times (17+81+2)`
`= 36 \times 100`
`= 3600`
`42 \times 17 + 58 \times 83 \times 42 \times 83 + 42 \times 83 + 17`
`= 17 \times (42+58) + 42 \times 83 \times (58 \times 83 +1)`
`= 17 \times 100 + 3486 \times 4815`
`= 1700 + 16785090`
`= 16786790`
Tính nhẩm:
a) 66 - 60 = 98 - 90 = 72 - 70 =
78 - 50 = 59 - 30 = 43 - 20 =
b) 58 - 4 = 67 - 7 = 99 - 1 =
58 - 8 = 67 - 5 = 99 - 9 =
a) 66 - 60 = 6 98 - 90 = 8 72 - 70 = 2
78 - 50 = 28 59 - 30 = 29 43 - 20 = 23
b) 58 - 4 = 54 67 - 7 = 60 99 - 1 = 98
58 - 8 = 50 67 - 5 = 62 99 - 9 = 90
a) 66 - 60 = 6 98 - 90 = 8 72 - 70 = 2
78 - 50 = 28 59 - 30 = 29 43 - 20 = 23
b) 58 - 4 = 54 67 - 7 = 60 99 - 1 = 98
58 - 8 = 50 67 - 5 = 62 99 - 9 = 90