=1/2.3+1/3.4+1/4.5+1/5.6
=1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6
=1/2-1/6
=1/3
=1/2.3+1/3.4+1/4.5+1/5.6
=1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6
=1/2-1/6
=1/3
tinh bang cach thuan tien nhat a.3/5+4/7+2/5+1/7+2/7 b.1/3+1/6+4/3+2/6+2/3
tinh bang cach thuan tien nhat
1+2+3+4+5+6+7+8+9:9 =
Bài 1. Tính bằng cách thuận tiện nhất:
a)(1/3+1/5)x1/4 b)5/3 x 4/5 x 6/7 c) 2/5 x 3/7 + 2/5 x 4/7
tinh bang cach thuan tien:
3/5+4/7+2/5+1/7+2/7=
giup minh
tinh bang cach thuan tien
3/7 x 5/6 + 4/7 x 5/6
tinh bang hai cach a)3/4 x 1/2 x 2
cach 1 : .....................................................
cach 2 : .....................................................
b) (3/4 + 1/2) x 5?7
cach 1 : .................................................................
cach 2 : .................................................................
tinh bang cach thuan tien nhat
a) 2/5 + 1/6 + 3/5
b) 9/13 + 4/13 + 2/3
tinh bang cach thuan tien nhat
1/2+1/6+1/12+1/20
1/2+1/6+1/12+1/20+.........+19900
1/2+1/3+1/4+1/8+1/16
1/2+1/3+1/4+1/8+1/16+.......+1/512
tinh gia tri bieu thuc sau bang hai cach:
a,1/2 x 1/3+1/3 x1/5
b,{2/5+3/10} x 1/2