2 + 2 = :
3 + 3 =?
6 + 987 = ?
999 + 1 = ?
999 . 987 + 987
999 . 987 + 987
=999.987+999.987
=987.(999+1)
=987.1000
=987000
999 NHÂN 987+987
= 98700
HỌC TỐT ~.~
1972026
à quên 1 số 0 !!
= 987 000
Hãy đọc số sau :
102 987
74 865
3 762 999
Một trăm linh hai nghìn chín trăm tám mươi bảy
bảy mươi tư nghìn tám trăm sáu mươi lăm
ba triệu bảy trăm sáu mươi hai nghìn chím trăm chín mươi chín.
so sánh m=1/2*3/4*5/6...999/1000;n=2/3*3/4....998/999
14/6+1/9+19/13+17/9+7/13+4/6( tính nhanh)
Tìm x
A)X/12=3/8
B) x+987+16=1996+987+16
C) ( 1/2-1/3+1/4): (1/6-1/×)=17,5
D) x×4,5-1,3×x=48,48
Gíup mk nha mn ơi
(1/99+12/999+123/999).(1/2-1/3-1/6)
( 1/99 + 12/999 + 123/999 ) . ( 1/2 - 1/3 - 1/6 )
= ( 1/99 + 12/999 + 123/999 ) . 0
= 0 nha bn
Rút gọn biểu thức:
A= 1+1/2+1/2^2+1/2^3+...+1/2^2012
B= ( 1/99+12/999+123/999)(1/2-1/3-1/6)
\(2A=2+1+\frac{1}{2}+\frac{1}{2^2}+...+\frac{1}{2^{2011}}\)
=> \(2A-A=\left(2+1+\frac{1}{2}+\frac{1}{2^2}+...+\frac{1}{2^{2011}}\right)-\left(1+\frac{1}{2}+\frac{1}{2^2}+...+\frac{1}{2^{2012}}\right)\)
=> \(A=2-\frac{1}{2^{2012}}=\frac{2^{2013}-1}{2^{2012}}\)
\(A=1+\frac{1}{2}+\frac{1}{2^2}+\frac{1}{2^3}+...+\frac{1}{2^{2012}}\)
\(2A=2\left(1+\frac{1}{2}+\frac{1}{2^2}+\frac{1}{2^3}+...+\frac{1}{2^{2012}}\right)\)
\(2A=3+\frac{1}{2}+\frac{1}{2^2}+\frac{1}{2^3}+...+\frac{1}{2^{2011}}\)
\(2A-A=A\)
\(=\left(3+\frac{1}{2}+\frac{1}{2^2}+\frac{1}{2^3}+...+\frac{1}{2^{2011}}\right)-\left(1+\frac{1}{2}+\frac{1}{2^2}+\frac{1}{2^3}+...+\frac{1}{2^{2012}}\right)\)
\(=3+\frac{1}{2}+\frac{1}{2^2}+\frac{1}{2^3}+...+\frac{1}{2^{2011}}-1-\frac{1}{2}-\frac{1}{2^2}-\frac{1}{2^3}-...-\frac{1}{2^{2012}}\)
\(=2-\frac{1}{2012^2}\)
\(B=\left(\frac{1}{99}+\frac{12}{999}+\frac{123}{9999}\right)\cdot\left(\frac{1}{2}-\frac{1}{3}-\frac{1}{6}\right)\)
\(B=\left(\frac{1}{99}+\frac{12}{999}+\frac{123}{9999}\right)\cdot\left(\frac{6}{12}-\frac{4}{12}-\frac{2}{12}\right)\)
\(B=\left(\frac{1}{99}+\frac{12}{999}+\frac{123}{9999}\right)\cdot0=0\)
q=(1/99+12/999+123/999)*(1/2-1/3-1/6)
q = (1/99+12/999+123/999)*(1/2-1/3-1/6)
= (1/99+12/999+123/999) * 0
= 0
Q= (1/99+12/999+123/999)(1/2-1/3-1/6)
\(Q=\left(\frac{1}{99}+\frac{12}{999}+\frac{123}{999}\right).\left(\frac{1}{2}-\frac{1}{3}-\frac{1}{6}\right)\))
\(Q=\left(\frac{1}{99}+\frac{12}{999}+\frac{123}{999}\right).0=0\)