0.9*110+9*3.2+90*0.28
2+4+6+8+......+32
0.9 * 50 + 9 * 3.2 + 90 * 0.28
0.9*50 + 9*3.2 +90*0.28
=0.9*10*5 + 9*3.2 + 9*10*0.28
=9*5 + 9*3.2 + 9*2.8
=9*( 5+3.2+2.8)
=9*11
=99
k cho mình nha, mình k lại
0.9*50 + 9*3.2 + 90*0.28
= 0.9*10*5 + 9*3.2 + 9*10*0.28
=9*5 + 9*3.2 + 9*28
=9*(5+3.2+28)
=9*36.2
=325.8
K CHO MÌNH NHA BẠN
tính nhanh:
0.9*50+9*3.2+90*0.28
các bạn ơi giúp mình với
0.9 x 50 + 9 x 3.2 + 90 x 0.28
=0.9x10x5 + 9x3.2 + 9x10x0.28
=9x5 + 9x3.2 + 9x2.8
=9(5+3.2+2.8)
=9x11
=99
k mình nha, mình nhanh nhất
Rút gọn
1) (0.9)^5/(0.3)^6
2)20^5*5^410/100^5
3)4^6*9^5+6^9*120/8^4*3^12-6^11
4)4^2*25^2+32*125/2^3*5^2
1, 3^4
2, 5^405
3, -20/3
4, 4
KHÔNG BÍT ĐÚNG HAY KO =>HIHIHIHI
chứng minh :
A = 1+3+4+5+6+7+8+9+....+999999 chia hết cho 96
B = 8*8*8*8*8*8*....*8*9 chia hết cho 72
C = 80+90+100+110+....+9000 chia hết cho 3
D =(72+89)*(72+90)*(72+91)*.....*(72+300) chia hết cho 8
E = -2+-3+-4+-5+-6+-7+-8+-9+.......+-98 chia hết cho 0
: tí
Câu 1: tính
a) 19.64+36.19
b) 150-[102-(14-11)2.20070
c) 22.3-(110+8):32
d) 59-[90-(17-8)2].14514
e) 72-36:3
nh
a) 19.64+36.19
b) 150-[102-(14-11)2.20070
c) 22.3-(110+8):32
d) 59-[90-(17-8)2].14514
e) 72-36:32
Tính nhanh: A. 1/2 +1/4+1/8+1/16+1/32+1/64+1/128. B. 1/2 + 1/6 + 1/12 + 1/20 + 1/30 + 1/42 + 1/56 + 1/72 + 1/90 + 1/110 Các bạn giúp mình với mình cảm ơn
a: \(A=\dfrac{1}{2}+\left(\dfrac{1}{2}\right)^2+\left(\dfrac{1}{2}\right)^3+...+\left(\dfrac{1}{2}\right)^7\)
=>\(2\cdot A=1+\dfrac{1}{2}+\left(\dfrac{1}{2}\right)^2+...+\left(\dfrac{1}{2}\right)^6\)
=>\(2A-A=1-\left(\dfrac{1}{2}\right)^7=1-\dfrac{1}{128}=\dfrac{127}{128}\)
=>\(A=\dfrac{127}{128}\)
b: \(B=\dfrac{1}{1\cdot2}+\dfrac{1}{2\cdot3}+...+\dfrac{1}{10\cdot11}\)
\(=1-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+...+\dfrac{1}{10}-\dfrac{1}{11}\)
\(=1-\dfrac{1}{11}=\dfrac{10}{11}\)
9/10 = 0.9 ; 90/100 = 0.90 . Ta thấy 0.9 = 0.9 vì
em học trước nha
tìm x biết
\(x+\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+...+\frac{1}{90}=\frac{4}{3}\times\frac{9}{8}\times\frac{16}{15}\times....\times\frac{100}{99}+\frac{9}{110}\)
ta gọi \(\frac{1}{2}+\frac{1}{6}+...+\frac{1}{90}\)là A
\(A=\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{9.10}\)
\(\Leftrightarrow1.\left(\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+....+\frac{1}{9}-\frac{1}{10}\right)\)
\(\Rightarrow A=1-\frac{1}{10}=\frac{9}{10}\)
ta gọi B là biểu thức thứ2
\(B=\frac{2.2}{3}\times\frac{3.3}{2.4}\times\frac{4.4}{3.5}\times...\times\frac{10.10}{9.11}\)
\(\Rightarrow\)2 x \(\frac{10}{11}\)\(=\frac{20}{11}\)
\(\Rightarrow\)\(x+\frac{9}{10}=\frac{20}{11}+\frac{9}{110}\)
\(\Rightarrow x=1\)
mk nghĩ vậy bạn ạ, mk mong nó đúng
Câu 1: tính
a) 19.64+36.19
b) 150-[102-(14-11)2.20070
c) 22.3-(110+8):32
d) 59-[90-(17-8)2].14514
e) 72-36:32
a) Ta có: \(19\cdot64+36\cdot19\)
\(=19\cdot\left(64+36\right)\)
\(=19\cdot100=1900\)
b) Ta có: \(150-\left[10^2-\left(14-11\right)^2\cdot2700^0\right]\)
\(=150-\left[100-3^2\cdot1\right]\)
\(=150-91\)
\(=69\)
c) Ta có: \(22^3-\left(1^{10}+8\right):3^2\)
\(=22^3-\left(1+8\right):3^2\)
\(=22^3-9:9\)
\(=22^3-1\)
\(=10647\)
d) Ta có: \(59-\left[90-\left(17-8\right)^2\right]\cdot1^{4514}\)
\(=59-\left[90-9^2\right]\cdot1\)
\(=59-\left(90-81\right)\)
\(=59-9=50\)
e) Ta có: \(7^2-36:3^2\)
\(=7^2-36:9\)
\(=49-4=45\)