bài 1: tính nhanha, 2 x 3 x 4 x 8 x 50 x 25 x 125 b, 45 x 128 - 90 x 64c, 0,48 x 500 - 2,4 x 40 x2 c, 0,48 x 500 - 2,4 x 40 x2 d, 1998 x 1996 + 1997 x 11 +1985 trên 1997x1996-1995x1996Ai làm nhanh mình tik , mình đag cần gấp,...
Đọc tiếp
bài 1: tính nhanh
a, 2 x 3 x 4 x 8 x 50 x 25 x 125 b, 45 x 128 - 90 x 64c, 0,48 x 500 - 2,4 x 40 x2 c, 0,48 x 500 - 2,4 x 40 x2 d, 1998 x 1996 + 1997 x 11 +1985 trên 1997x1996-1995x1996
Ai làm nhanh mình tik , mình đag cần gấp, cảm ơn
a, 2 x 3 x 4 x 8 x 50 x 25 x 125 b, 45 x 128 - 90 x 64
= ( 2 x 50 ) x ( 4 x 25 ) x ( 8 x 125 ) x 3 = 45 x ( 128 - 2 x 64 )
= 100 x 100 x 1000 x 3 = 45 x 0
= 30000000 = 0
c, 0,48 x 500 - 2,4 x 40 x 2
= 0,48 x 100 x 5 - 2,4 x 10 x 4 x 2
= 48 x 5 - 24 x 8
= 24 x ( 2 x 5 - 8 )
= 24 x 2
= 48
d, \(\frac{1998\times1996+1997\times11+1985}{1997\times1996-1995\times1996}\)
\(=\frac{1998\times1996+\left(1996+1\right)\times11+1985}{1996\times\left(1997-1995\right)}\)
\(=\frac{1998\times1996+1996\times11+11+1985}{1996\times2}\)
\(=\frac{1998\times1996+1996\times11+1996}{1996\times2}\)
\(=\frac{1996\times\left(1998+11+1\right)}{1996\times2}\)
\(=\frac{1996\times2010}{1996\times2}\)
\(=\frac{2010}{2}\)
\(=1005\)
a, \(2.3.4.8.50.25.125\)
\(=\left(2.50\right)\left(4.25\right)\left(8.125\right).3\)
\(=100.100.1000.3\)
\(=10000000.3\)
\(=30000000\)
b, \(45.128-90.64\)
\(=45.2.64-90.4\)
\(=90.64-90.64\)
\(=0\)
c, \(0,48.500-2,4.40.2\)
\(=0,48.100.5-2,4.2.10.4\)
\(=48.5-4,8.10.4\)
\(=48.5-48.4\)
\(=48\left(5-4\right)\)
\(=48.1\)
\(=48\)
d, \(\frac{1998.1996+1997.11+1985}{1997.1996-1995.1996}\) \(\)
\(=\frac{1998.1996+\left(1996+1\right).11+1985}{1996\left(1997-1995\right)}\)
\(=\frac{1998.1996+1996.11+11+1985}{1996.2}\)
\(=\frac{1998.1996+1996.11+1996}{1996.2}\)
\(=\frac{1996\left(1998+11+1\right)}{1996.2}\)
\(=\frac{1998+11+1}{2}\)
\(=\frac{2010}{2}\)
\(=1005\)