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a. 45.34 + 45.37 + 71.23 + 33.71
= 45.(34 + 37) + 71.(23 + 33)
= 45.71 + 71.56
= 71.(45 + 56)
= 71 . 101
= 7171
a) \(45.34+45.37+71.23+33.71=45\left(34+37\right)+71\left(23+33\right)=45.71+71.56=71\left(45+56\right)=71.101=7171\)
b) \(23.46+23.52+98.35+98.42=23\left(46+52\right)+98\left(35+42\right)=23.98+98.77=98\left(23+77\right)=98.100=9800\)
c) \(27.34+27.56+90.20+26.90=27\left(34+56\right)+90\left(20+26\right)=27.90+90.46=90\left(27+46\right)=90.73=6570\)
d) \(12.37+12.78+115.29+115.59=12\left(37+78\right)+115\left(29+59\right)=115.12+115.88=115\left(12+88\right)=115.100=11500\)
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d. 12.37 + 12.78 + 115.29 + 115.59
= 12 . ( 37 + 78 ) + 115 . ( 29 + 59 )
= 12 . 115 + 115 . 88
= ( 12 + 88 ) . 115
= 100 . 115
= 11 500
a. 45.34 + 45.37 + 71.23 + 33.71
= 45 . ( 34 + 37 ) + 71 . ( 23 + 33 )
= 45 . 71 + 71 . 56
= ( 45 + 56 ) . 71
= 101 . 71
= ( 100 + 1 ) . 71
= 7100 + 71
= 7171
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\(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{14.15}+\frac{1}{15.16}\)
\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{14}-\frac{1}{15}+\frac{1}{15}-\frac{1}{16}\)
\(=1-\frac{1}{16}\)
\(=\frac{15}{16}\)
Chúc bạn học giỏi nha!!!
K cho mik vs nhé
1/1.2+1/2.3+1/3.4+.........+1/14.15+1/15.16
=1-1/2+1/2-1/3+...+1/15-1/16
=1-1/16
=15/16 *k mk nha*
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20,16x45,23+40,32x41,27-20,16x27,77
=20,16x45,23+20,16x2x41,27-20,16x27,77
=20,16x(45,23+2+41,27-27,77)
=20,16x60,73
=1224,3168
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y:8+yx8-56,78=69,11x2
y:8+yx8-56,78=138,22
y:8+yx8=138,22+56,78
y:8+yx8=195
chịu
CHÚC BẠN HỌC GIỎI
TK MÌNH NHÉ
y : 8 + y x 8 - 56.78 = 69.11 x 2
y : 8 + y x 8 - 56.78 = 138.22
y : 8 + y x 8 = 138.22 + 56.78
y : 8 + y x 8 = 195
y x 0.125 + y x 8 = 195
y x ( 0.125 + 8 ) = 195
y x 8.125 = 195
y = 195 : 8.125
y = 24
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S = 1.2 + 2.3 + 3.4 + ... + 15.16
3S = 1.2.(3-0) + 2.3.(4-1) + 3.4.(5-2) + ... +15.16.(17-14)
3S = 1.2.3 - 0.1.2 + 2.3.4 - 1.2.3 + 3.4.5 - 2.3.4 + ... + 15.16.17 - 14.15.16
3S = 15.16.17
S = 5.16.17
S = 1360
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\(\left(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}\right):x=\frac{3}{1.2}+\frac{3}{2.3}+\frac{3}{3.4}+...+\frac{3}{15.16}\)
\(\left(\frac{8}{16}+\frac{4}{16}+\frac{2}{16}+\frac{1}{16}\right).\frac{1}{x}=3.\left(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{15.16}\right)\)
\(\frac{8+4+2+1}{16}.\frac{1}{x}=3.\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{15}-\frac{1}{16}\right)\)
\(\frac{15}{16}.\frac{1}{x}=3.\left(1-\frac{1}{16}\right)\)
\(\frac{15}{16}.\frac{1}{x}=3.\frac{15}{16}\)
=> \(\frac{1}{x}=3\)
=> \(x=\frac{1}{3}\)
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A x 2 = 2 + 4 + 8 + ....................... + 16384
A x 2 – A = 16384 – 1 = 16383
Vậy A = 16383
a) \(45,23+56,78-12\cdot10\)
a = 89,91
b =24,78913
c = không biết và minh nha kết bạn nữa