Bài 4: Tính bằng cách thuận tiện
a. 6 x 125 x 275 x 4
b. 245 x 24 + 38 x 374 + 12 x 310 + 213 x 76
c. 4 x 826 x 125 x 2
d. 625 x 150 x 4 x 4
Rất rất rất rất rất rất gấpppppppppppp
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(4\times826\times125\times2\\=(4\times2\times125)\times826\\=(8\times125)\times826\\=1000\times826\\=826000\)
4 x 826 x 125 x 2
= (4 x 125 ) x ( 826 x 2 )
= 500 x 1652
= 826000
#HOK TỐT#
Có 4 x 826 x 125 x 2
=(4\(\times\)2)\(\times\)125\(\times\)826
=8\(\times\)125\(\times\)826
=1000\(\times\)826=826000
Hok tốt
Thuận
3 x 6 + 3 x 70 + 24 x 3
= 3 x (6 + 70 + 24)
= 3 x 100
= 300
3 x 6 + 3 x 70 + 24 x 3
= 3 x (6 + 70 + 24)
= 3 x 100 = 300
a. = 0,25 : 0,25 + 0,4 x 2,5 + 0,2 x 5
= 1 + 1 + 1
= 3
b. y x ( 7 + 1 + 12 - 6 - 4) = 45
y x 9 = 45
=> y = 5
a: =2(3h15'+4h45')=2x8h=16h
b: =(24'30s+25'30s):5
=50':5=10'
a) C1
\(\dfrac{1}{8}\times\dfrac{5}{6}+\dfrac{5}{6}\times\dfrac{2}{3}=\dfrac{5}{6}\times\left(\dfrac{1}{8}+\dfrac{2}{3}\right)=\dfrac{5}{6}\times\dfrac{19}{24}=\dfrac{95}{144}\)
C2
\(\dfrac{1}{8}\times\dfrac{5}{6}+\dfrac{5}{6}\times\dfrac{2}{3}=\dfrac{5}{48}+\dfrac{10}{18}=\dfrac{95}{144}\)
b) C1
\(\dfrac{7}{5}\times\dfrac{3}{4}-\dfrac{1}{2}\times\dfrac{3}{4}=\dfrac{3}{4}\times\left(\dfrac{7}{5}-\dfrac{1}{2}\right)=\dfrac{3}{4}\times\dfrac{9}{10}=\dfrac{27}{40}\)
C2
\(\dfrac{7}{5}\times\dfrac{3}{4}-\dfrac{1}{2}\times\dfrac{3}{4}=\dfrac{21}{20}-\dfrac{3}{8}=\dfrac{27}{40}\)
c) C1
\(\left(\dfrac{5}{6}+\dfrac{5}{8}\right)\times\dfrac{2}{3}=\dfrac{35}{24}\times\dfrac{2}{3}=\dfrac{35}{36}\)
C2
\(\left(\dfrac{5}{6}+\dfrac{5}{8}\right)\times\dfrac{2}{3}=\left(\dfrac{5}{6}\times\dfrac{2}{3}\right)+\left(\dfrac{5}{8}\times\dfrac{2}{3}\right)=\dfrac{5}{9}+\dfrac{5}{12}=\dfrac{35}{36}\)
a. \(P=\left(\dfrac{\sqrt{x}}{\sqrt{x}-2}-\dfrac{4}{x-2\sqrt{x}}\right)\cdot\left(\dfrac{1}{\sqrt{x}+2}+\dfrac{4}{x-4}\right)\)
<=> \(P=\left(\dfrac{\sqrt{x}}{\sqrt{x}-2}-\dfrac{4}{\sqrt{x}\left(\sqrt{x}-2\right)}\right)\cdot\dfrac{\sqrt{x}-2+4}{\left(\sqrt{x}+2\right)\left(\sqrt{x}-2\right)}\)
<=> \(P=\dfrac{x-4}{\sqrt{x}\left(\sqrt{x}-2\right)}\cdot\dfrac{\sqrt{x}+2}{\left(\sqrt{x}+2\right)\left(\sqrt{x}-2\right)}\)
<=> \(P=\dfrac{\sqrt{x}+2}{x-2\sqrt{x}}\)
b. Khi \(x=7+4\sqrt{3}=\left(2+\sqrt{3}\right)^2\) => \(\sqrt{x}=2+\sqrt{3}\)
=> \(P=\dfrac{2+\sqrt{3}+2}{7+4\sqrt{3}-2\left(2+\sqrt{3}\right)}=\dfrac{4+\sqrt{3}}{7+4\sqrt{3}-4-2\sqrt{3}}=\dfrac{4+\sqrt{3}}{3+2\sqrt{3}}=\dfrac{5\sqrt{3}-6}{3}\)
check giùm mik
a. 4x 125 x 6 x 275
= 500 x 1650
= 825 00
b. = 5880 + 14 212 + 3720 + 16 188
= ( 5880 + 3720 ) + ( 14212 + 16 188 )
= 9 600 + 30 400
= 40 000
c. = (4 x 145) x (2 x 826)
= 500 x 1652
= 826 000
d. = (635 x 4) x (150 x 4)
= 2 500 x 600
= 1 500 000