Bài 1:
a) 8 x 4 x 125 x 25
= ( 8 x 125 ) x ( 4 x 25 )
= 1000 x 100
= 100000
b) 2 x 178 x 5
= ( 2 x 5 ) x 178
= 10 x 178
= 1780
Bài 2:
a) 5/7 + 7/13 + 9/13 + 6/5 + 9/7 + 9/5
= ( 5/7 + 9/7 ) + ( 7/13 + 9/13 ) + ( 6/5 + 9/5 )
= 2 + 16/13 + 3
= 81/13
b) 1/11 + 2/11 + ... + 10/11
= 55/11 = 5
Tính
a) 4/3*7 + 4/7*11 + 4/11*15 + 4/15*19 + 4/19*23 + 4/23*27
b) 1/2*3 + 1/3*4 + 1/4*5 + 1/5*6 +1/6*7
c) 2/3*5 + 2/5*7 + 2/7*9 + 2/9*11 + 2/11*13 + 2/1*2 + 2/2*3 + 2/3*4 + 2/8*9 + 2/9*10
tính nhanh
a 5/11+7/13+3/8+10/13+6/11+5/8+9/13
b 1/2nhân 9/10+1/2 nhân 8/10+1/2 nhân 8/10
Tính nhanh:
a.3/5 *7/9 +11/9 *3/5 -3/10 =
b,14/13:1/2 +3/13 *2 -2*7/13=
B=1/4*7+1/4*9+1/5*9+1/5*11+1/6*11+1/6*13+1/7*13
Tìm B nha.
a/2-3+5-7+9-11+13-15+17
b/1/1×2+1/2×3+1/3×4+1/4×5+1/5×6+1/6×7+1/7+8+1/8×9
1/4*7+1/4*9+1/5*9+1/5*11+1/6*11+1/6*13+1/7*13
tất cả là hỗn số
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10
2 + 4 + 6 + 8 + 10 + 12 + 14 + 16 + 18 + 20
1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19
a[11+13+15+17+19]-/10+12+14+16+18]
b /9+7+5+3+1]-/8+6+4+2]
1+2+3+4+5+6+7+8+9+10+11+12+13+141+5
