19x27+47x81+19x20
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19×27+47×81+19×20
=19×(27+20)+47×81
=19×47+47×81
=47×(19+81)
=47×100
=4700.
19x27+47x81+19x20
=19x27+19x20+47x81
=19x(27+20)+47x81
=19x 47 +47x81
=19x 47 +81x47
=(19+81)x47
= 100 x47
= 4700.
K nhé bạn ơi.
a)\(48x19+48x115+134x52\)
\(=48x\left(19+115\right)+134x52\)
\(=48x132+132x52\)
\(=132x\left(48+52\right)\)
\(=132x100=13200\)
b)\(27x121-87x27+73x34\)
\(=27x\left(121-87\right)+73x34\)
\(=27x34+73x34\)
\(=34x\left(27+73\right)\)
\(=34x100=3400\)
c)\(125x98-125x46-52x25\)
\(=125x\left(98-46\right)-52x25\)
\(=125x52-52x25\)
\(=52x\left(125-25\right)\)
\(=52x100=5200\)
d)\(136x23+136x17-40x36\)
\(=136x\left(23+17\right)-40x36\)
\(=136x40-40x36\)
\(=40x\left(136-36\right)\)
\(=40x100=4000\)
e)\(17x93+116x83+17x23\)
\(=17x\left(93+23\right)+116x83\)
\(=17x116+116x83\)
\(=116x\left(17+83\right)\)
\(=116x100=11600\)
g)\(19x27+47x81+19x20\)
\(=19x\left(27+20\right)+47x81\)
\(=19x47+47x81\)
\(=47x\left(19+81\right)\)
\(=47x100=4700\)
h)\(87x23+13x93+70x87\)
\(=87x\left(23+70\right)+13x93\)
\(=87x93+13x93\)
\(=93x\left(87+13\right)\)
\(=93x100=9300\)
Mk đã mất công zậy rùi nên mong mọi người k mk nhé
a) = 13400
b) = 4714
c) = 5200
d) = 4000
e) = 11600
g) = 4700
h) = 9300
a,48x19+48x115+124x52
=48x(19+115)+124x52
=48x124+124x52
=124x(48+52)
=124x100
=12400
b,27x121-87x27+73x34
=27x(121-87)+73x34
=27x34+73x34
=34x(27+73)
=34x100
=3400
c,125x98-125x46-52x25
=125x(98-46)-52x25
=125x52-52x25
=52x(125-25)
=52x100
=5200
d,136x23+136x17-40x36
=136x(23+17)-40x36
=136x40-40x36
=40x(136-36)
=40x100
=4000
e,17x93+116x83+17x23
=17x93+17x23+116x83
=17x(93+23)+116x83
=17x116+116x83
=116x(17+83)
=116x100
=11600
g,19x27+47x81+19x20
=19x27+19x20+47x81
=19x(27+20)+47x81
=19x47+47x81
=47x(19+81)
=47x100
=4700
h,87x23+13x93+70x87
=87x23+70x87+13x93
=87x(23+70)+13x93
=87x93+13x93
=93x(87+13)
=93x100
=9300
Nhớ like mik nhé!^-^ Mất bao thời gian của mik đấy!
(69.210.210) : (219.273+15.49.94)
=((2.3)9.(2.2)10): (219.(33)3+15.(22)9.(32)4)
= (29.39.(22)10) : (219.39+15.218.38)
= (29.39.220) : (218.38.(2.3+15))
= (29.39.22.218) :(218.38.21)
=(211.39.218) : (218.39.7)
=211:7
=\(\frac{2048}{7}\)
\(=\dfrac{1}{3}\left(1\times2\times3+2\times3\times3+...+19\times20\times3\right)\\ =\dfrac{1}{3}\left[1\times2\times\left(3-0\right)+2\times3\times\left(4-1\right)+...+19\times20\times\left(21-18\right)\right]\\ =\dfrac{1}{3}\left(1\times2\times3-1\times2\times3+2\times3\times4-...-18\times19\times20+19\times20\times21\right)\\ =\dfrac{1}{3}\times19\times20\times21=2660\)
Đặt A = 1×2 + 2×3 + 3×4 + ... + 19×20
⇒ 3A = 1×2×3 + 2×3×3 + 3×4×3 + ... + 19×20×3
= 1×2×3 + 2×3×(4 - 1) + 3×4×(5 - 2) + ... + 19×20×(21 - 18)
= 1×2×3 - 1×2×3 + 2×3×4 - 2×3×4 + 3×4×5 - ... - 18×19×20 + 19×20×21
= 19×20×21
= 7980
⇒ A = 7980 : 3 = 2660
Đặt \(A=\frac{2}{1.2}+\frac{2}{2.3}+\frac{2}{3.4}+....+\frac{2}{18.19}+\frac{2}{19.20}\)
\(A=2\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{18}-\frac{1}{19}+\frac{1}{19}-\frac{1}{20}\right)\)
\(A=2\left(1-\frac{1}{20}\right)\)
\(A=2.\frac{19}{20}=\frac{19}{10}\)
\(\frac{2}{1.2}+\frac{2}{2.3}+\frac{2}{3.4}+...+\frac{2}{18.19}+\frac{2}{19.20}\)
\(=2\left(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{18.19}+\frac{1}{19.20}\right)\)
\(=2\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{18}-\frac{1}{19}+\frac{1}{19}-\frac{1}{20}\right)\)
\(=2\left(1-\frac{1}{20}\right)\)
\(=2.\frac{19}{20}\)
\(=\frac{19}{10}\)
19x(27+20)+47x81
= 19x47+47x81
=47x(19+81)
=47x100
=4700
19x(27+20)+47x81
= 19x47+47x81
=47x(19+81)
=47x100
=4700