{ [ 6.x-72] ;2-84} . 28= 5628. tim sô tu nhien x
tinh nhanh 72 x 19 + 36 x 6 x 10 + 144 x 40 - 72 x 29
`= 72 xx 19 + 36 xx 2 xx3 xx 10 + 72 xx 80 - 72 xx 29`
`= 72 xx(19 + 30 - 29 + 80)`
`= 72 xx 100`
`= 7200`
\(=72.19+36.2.3.10+72.2.40-72.29\)
\(=72.19+72.30+72.80-72.29\)
\(=72.\left(19+30+80-29\right)\)
\(=72.100=7200\)
92/6 x 72/15 : (-72)/10
\(\dfrac{92}{6}\times\dfrac{72}{15}:\left(-\dfrac{72}{10}\right)\)
\(=\dfrac{92\times72}{6\times15}:\left(-\dfrac{72}{10}\right)\)
\(=\dfrac{368}{5}:\left(-\dfrac{72}{10}\right)\)
\(=\dfrac{368}{5}\times\dfrac{-10}{72}\)
\(=\dfrac{368\times\left(-10\right)}{5\times72}\)
\(=\dfrac{-92}{9}\)
\(=\dfrac{92}{6}\cdot\dfrac{72}{15}\cdot\dfrac{-10}{72}=\dfrac{92}{6}\cdot\dfrac{-2}{3}=\dfrac{-92}{9}\)
a) 8 x 427 x 3 + 6 x 573 x 4
b) 6 x 1235 x 20 – 5 x 235 x 24
c) (72 x 135 + 9 x 65 + 8) : 25 – 3500 : 25
d) (18 x 957 – 9 x 354 x 2 – 3 x 621 x 6) : 72
a: =24*1000=24000
b: =120*1000=120000
c: =72(135+65):25-140
=72*8-140=436
d: =18(957-354-621):72=-9/2
Tính nhẩm
9 x 6 = ...... 9 x 7 = ...... 9 x 5 = ...... 9 x 8 = ......
54 : 9 = ..... 63 : 9 = ..... 45 : 9 = ..... 72 : 9 = .....
54 : 6 = ..... 63 : 7 = ..... 45 : 5 = ..... 72 : 8 = .....
9 x 6 = 54 9 x 7 = 63 9 x 5 = 45 9 x 8 = 72
54 : 9 = 6 63 : 9 = 7 45 : 9 = 5 72 : 9 = 8
54 : 6 = 9 63 : 7 = 9 45 : 5 = 9 72 : 8 = 9
9 x 6 = 54 9 x 7 = 63 9 x 5 = 45 9 x 8 = 72
54 : 9 = 6 63 : 9 = 7 45 : 9 = 5 72 : 9 = 8
54 : 6 = 9 63 : 7 = 9 45 : 5 =9 72 : 8 =9
Tính nhẩm:
9 x 5 =
9 x 6 =
9 x 7 =
9 x 8 =
45 : 9 =
54 : 9 =
63 : 9 =
72 : 9 =
45 : 5 =
54 : 6 =
63 : 7 =
72 : 8 =
9 x 5 = 45
9 x 6 = 54
9 x 7 = 63
9 x 8 = 72
45 : 9 = 5
54 : 9 = 6
63 : 9 = 7
72 : 9 = 8
45 : 5 = 9
54 : 6 = 9
63 : 7 = 9
72 : 8 = 9
Tìm x biết:
a, (x + 72) × 4 = 320
b, (x - 56) × 7 = 749
c, (x + 3) × 4 = 36
d, (x - 5) × 6 = 72
tìm x
a, [(6 * x - 72) : 2 - 84] * 28 +5628
b, 72 : {16 - [47 + (x - 2)]} =8
c, x + 132 + 128 + 124 + ...+ 76 + 72 + 68 = 2016
(các bạn giải rõ ra nhé)
a,
52 x 378 + 49 x 387 - 387
b,
72 x 19 + 36 x 6 x 10 + 144 x 40 - 72 x 29
387×(52+49)-387
387×101-387
39087-387
38700
1368+216×10+576+2088
1368+2160+576-2088
3528+576-2088
4104-2088
2016
a/ 52.378+49.378-378
= 378 . (52+49 -1)
= 378 .100
= 37800
b/ 72 .19+36 .6.10+144 /40 -72.29
= 72 . 19 + 216 .10+576 .10 -72.29
= 72 .(19-29) +(216+576).10
= -72 .10 +792 .10
=720.10
= 7200
72 : x+180 : x=6
72 ÷ x + 180 ÷ x = 6
( 72 + 180 ) ÷ x = 6
252 ÷x = 6
x = 252 ÷ 6
= 42
ta có:
72 :x+180:x =6
(72+180):x=6
252:x=6
suy ra x=42
vậy x=42
72 : x + 180 : x = 6
72 + 180 : x = 6
252 : x = 6
x = 252 : 6
x = 42.
Mình chúc bạn học tốt nhé.
Bài 7: Tính bằng cách thuận tiện nhất
a) (25x32) : 8 b) 24 x 11 + 6 x 86 x 4 + 72
c) 36 x 5 + 9 x 79 x 4 + 72 x 8 d) (56x125) : 7
a) (25x32) : 8
= 25 x (4 x 8) : 8
= (25 x 4) x (8:8)
= 100 x 1
=100
b, 24 x 11 + 6 x 86 x 4 + 72
= 24 x 11 + (6 x 4) x 86 + 24 x 3
= 24 x 11 + 24 x 86 + 24 x 3
= 24 x (11+86+3)
= 24 x 100
= 2 400
\(\left(25\times32\right):8=25\times32:8=25\times\left(32:8\right)=25\times4=100\\ 24\times11+6\times86\times4+72\\ =24\times11+24\times86+24\times3\\ =24\times\left(11+86+3\right)\\ =24\times100=2400\\ 36\times5+9\times79\times4+72\times8\\ =36\times5+36\times79+36\times16\\ =36\times\left(5+79+16\right)\\ =36\times100=3600\\ \left(56\times125\right):7=56\times125:7=\left(56:7\right)\times125=8\times125=1000\)