Tính bằng hai cách:
a,(75+25):5
b,(84-24):4
c,(123+456):3
d,(936-306):6
K
Khách
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Những câu hỏi liên quan
HT
1
2 tháng 1 2021
C1 : = 630 : 6 = 105
C2 : = 936 : 6 - 306 : 6 = 156 - 51 = 105
CM
20 tháng 5 2017
a, Cách 1: 2 5 : 2 4 = 32 : 16 = 2 1
Cách 2: 2 5 : 2 4 = 2 1
b, Cách 1: 3 4 : 3 2 = 81:9 = 9 = 3 2
Cách 2: 3 4 : 3 2 = 3 2
c, Cách 1: 6 3 : 6 2 = 216 : 36 = 6 = 6 1
Cách 2: 6 3 : 6 2 = 6 1
d, Cách 1: 8 4 : 8 2 = 4096 : 64 = 64 = 8 2
Cách 2: 8 4 : 8 2 = 8 2
e, Cách 1: 7 5 : 7 4 = 16807 : 2401 = 7 = 7 1
Cách 2: 7 5 : 7 4 = 7 1
f, Cách 1: 100 3 : 100 = 1000000 : 100 = 10000 = 100 2
Cách 2: 100 3 : 100 = 100 2
11 tháng 11 2023
Đặt \(\dfrac{a}{b}=\dfrac{c}{d}=k\)
=>\(a=bk;c=dk\)
1: \(\dfrac{2a+3c}{2b+3d}=\dfrac{2\cdot bk+3\cdot dk}{2b+3d}=\dfrac{k\left(2b+3d\right)}{2b+3d}=k\)
\(\dfrac{2a-3c}{2b-3d}=\dfrac{2bk-3dk}{2b-3d}=\dfrac{k\left(2b-3d\right)}{2b-3d}=k\)
Do đó: \(\dfrac{2a+3c}{2b+3d}=\dfrac{2a-3c}{2b-3d}\)
2: \(\dfrac{4a-3b}{4c-3d}=\dfrac{4\cdot bk-3b}{4\cdot dk-3d}=\dfrac{b\left(4k-3\right)}{d\left(4k-3\right)}=\dfrac{b}{d}\)
\(\dfrac{4a+3b}{4c+3d}=\dfrac{4bk+3b}{4dk+3d}=\dfrac{b\left(4k+3\right)}{d\left(4k+3\right)}=\dfrac{b}{d}\)
Do đó: \(\dfrac{4a-3b}{4c-3d}=\dfrac{4a+3b}{4c+3d}\)
3: \(\dfrac{3a+5b}{3a-5b}=\dfrac{3bk+5b}{3bk-5b}=\dfrac{b\left(3k+5\right)}{b\left(3k-5\right)}=\dfrac{3k+5}{3k-5}\)
\(\dfrac{3c+5d}{3c-5d}=\dfrac{3dk+5d}{3dk-5d}=\dfrac{d\left(3k+5\right)}{d\left(3k-5\right)}=\dfrac{3k+5}{3k-5}\)
Do đó: \(\dfrac{3a+5b}{3a-5b}=\dfrac{3c+5d}{3c-5d}\)
4: \(\dfrac{3a-7b}{b}=\dfrac{3bk-7b}{b}=\dfrac{b\left(3k-7\right)}{b}=3k-7\)
\(\dfrac{3c-7d}{d}=\dfrac{3dk-7d}{d}=\dfrac{d\left(3k-7\right)}{d}=3k-7\)
Do đó: \(\dfrac{3a-7b}{b}=\dfrac{3c-7d}{d}\)
HB
1
20 tháng 11 2023
a: (-17)+5+8+17
\(=\left(-17+17\right)+\left(5+8\right)\)
=0+13
=13
b: \(\left(-24\right)+6+10+24\)
\(=\left(-24+24\right)+\left(6+10\right)\)
=0+16
=16
c: \(\left(-24\right)+6+\left(-10\right)+24\)
\(=\left(-24+24\right)+\left(6-10\right)\)
=0+(-4)
=-4
d: \(\left(-456\right)+2021-544\)
\(=2021-\left(456+544\right)\)
=2021-1000
=1021
e: \(\left(-1075\right)-29-\left(-1075\right)\)
\(=-1075+1075-29\)
=0-29
=-29
f: \(\left(-135\right)+48+140-\left(-5\right)\)
\(=48+\left(-135+140+5\right)\)
=48+10
=58
g: \(329+64+\left(-394\right)+36\)
\(=\left(329-394\right)+\left(64+36\right)\)
=100-65
=35
h: \(\left(-427\right)+\left(-123\right)+23+27\)
\(=\left(-427+27\right)+\left(-123+23\right)\)
=-400-100
=-500
\(a,C1:\left(75+25\right):5=100:5=20\\ C2:\left(75+25\right):5=75:5+25:5=15+5=20\)
\(b,C1:\left(84-24\right):4=60:4=15\\ C2\left(84-24\right):4=84:4-24:4=21-6=15\)
\(c,C1:\left(123+456\right):3=579:3=193\\ C2:\left(123+456\right):3=123:3+456:3=41+152=193\)
\(d,C1:\left(936-306\right):6=630:6=105\\C2:\left(936-306\right) :6=936:6-306:6=156-51=105\)
a,(75 + 25) : 5
C1: 100 : 5 = 20
C2: 75 : 5 + 25 : 5 = 15 + 5 = 20
b,(84 - 24) : 4
C1: 60 : 4 = 15
C2: 84 : 4 - 24 : 4 = 21 - 6 = 15
c,(123 + 456) : 3
C1: 579 : 3 = 193
C2: 123 : 3 + 456 : 3 = 41 + 152 = 193
d,(936 - 306) : 6
C1: 630 : 6 = 105
C2: 936 : 6 - 306 : 6 = 156 - 51 = 105