1/9 - 1/3 - 2/3 + 8/9
= (1/9+8/9) - (1/3+2/3)
= 1 - 1
=0
Vay ket qua la 0. cho y kien voi , neu dung thi k cho minh voi
1/9 - 1/3 - 2/3 + 8/9
= (1/9+8/9) - (1/3+2/3)
= 1 - 1
=0
Vay ket qua la 0. cho y kien voi , neu dung thi k cho minh voi
Tính nhanh
1×2×3×4×5×6×7×8×9×10×11×12×13×14×15×16×17×18×19×20
Tính nhanh1*3+3*5+5*7+7*9+......+99*101
tính nhanh
1/7 x 21/8 - 3/8 x 1/7 -1/7 x 2/8
tinh
a) 3/5 x 7/8 : 10/9
b) 3 2/7 x 2 1/4 : 1 2/5
c) 6/9 + 24/15 + 12/9 + 6/15
d) 3 2/9 - ( 1 5/8 + 1 2/9 )
Tinh nhanh
A=1/1*2+1/2*3+1/3*4+1/4*5+1/5*6+1/6*7+1/7*8+1/8*9+1/9*10
Tinh Nhanh:
6 2/7 + 7 3/5 + 8 6/9 + 9 1/4 +2/5 + 5/7 + 1/3 + 3/4 + 1967
bai 1:tinh nhanh hon so
a, 11 2/9+8 3/5+8 7/9+ 1 2/5
b, 4 2/3+5 1/2+1/3+4 1/2
c, 19 2/7+5 3/4+4 1/4-9 2/7
bai 2:hinh chu nhat co chieu dai 2 3/4m, chieu rong kem chieu dai la 1 1/2m. tinh chu vi va dien tich hinh chu nhat do.
1) tinh tổng 1+2+3+4+5+6+7+8+9+10
1. Tinh bang 2 cach
a) 8/15 : 2/3+7/15 :2/3
b) 4/9 x 3/5 +5/9 x3/5