`2/3:5/7xx5/5:2/3+1934`
`=2/3xx7/5xx5/7xx3/2+1934`
`=[2xx7xx5xx3]/[3xx5xx7xx2]+1934`
`=1+1934=1935`
2/3 : 5/7 x 5/7 :2/3 +1934
= (2/3 : 2/3)x(5/7 : 5/7) +1934
= 1x1+1934
= 1 +1934
= 1935
tính nhanh
a)\(\frac{2}{3}:\frac{5}{7}\cdot\frac{5}{7}:\frac{2}{3}+1934\)
b) \(\frac{1}{5}:\frac{1}{3}\cdot\frac{1:3}{1:5}+1996\)
Bài 7 :Tính nhanh:
a) 2/3:5/7x5/7:2/3+1934
b) (30 : \(7\frac{1}{2}\)+0,5 x 3 -1,5 ) x (\(4\frac{1}{2}-\frac{9}{2}\)) : ( 14,5 x 1000 )
c) (1999 x 1998 + 1998 x 1997 ) x ( 1 + 1/2 : 1\(\frac{1}{2}\)-1\(\frac{1}{3}\))
Bài 7 :Tính nhanh:
a) 2/3:5/7x5/7:2/3+1934
b) (30 : 7\(\frac{1}{2}\) +0,5 x 3 -1,5 ) x (4\(\frac{1}{2}\)−\(\frac{9}{2}\)) : ( 14,5 x 1000 )
c) (1999 x 1998 + 1998 x 1997 ) x ( 1 + 1/2 : 1\(\frac{1}{2}\) -1\(\frac{1}{3}\) )
Tính nhanh
3/4×5/7+3/2×2/7+5/4×3/
Tính bằng cách nhanh nhất:
b) 9 1 4 + 6 2 7 + 7 3 5 + 8 2 3 + 2 5 + 1 3 + 5 7 + 3 4
tính nhanh :
3 2/7-2/5+5/7-3/5
tính nhanh 2/3*5+2/5*7+/7*9+....2/13*15
Tính nhanh
1) A=1×5+2×6+3×7+...+20×24
2) A=1×2×3+2×3×5+3×5×7+...+21×23×25
Tính nhanh:
a.3/5 *7/9 +11/9 *3/5 -3/10 =
b,14/13:1/2 +3/13 *2 -2*7/13=
