cho a/2 = 1/1*2*3+ 2/2*3*4+3/5*6*7+...+100/199*200*201 tính A/2
Tính hợp lý
C= 1+2+4+8+16+.......+1024
D=1+2-3-4+5+6-7-8+9+....................+197+198-199-200+201
A = 1-2+3-4+5-6+.....+97-98+99-100+101
B = 1+2-3-4+5+6-7-8+......+98-99-100+101
2. Tính: A) 2/3 + 5/6 + 1/18. B) 3/4 + 2/25 + 7/100. C) 1/12 + 1/6 + 3/4.
Bài 1:Tính
a,3/2+5/4+5/8
b,4/5-3/8+2/4
c,3+6/8-5/4
d,5/6-1/2+2
e,3/5+6/11+7/13+2/5+16/11+19/13
g,75/100+18/21+29/32+1/4+3/21+13/32
Giusp mình nhé
so sánh
1+2+1+3+1+4+...+1+100 với 1+3+5+7+9+...+301
1+3+5+7+9+...+3999 với 2+4+6+8+...+3998+1,25
tính nhanh
4/5-2/3/+1/5-1/3
2/5 x 7/4 - 2/5x3/7
13/4 x 2/3 x 4/13 x 3/12
75/100 + 18/21 + 19/32 +1/4 + 3/21 + 13/32
2/5 + 6/9+3/4+3/5+1/3+1/4
tinh nhanh 1-2+3-4+5-6+7.................-100+101
1+2+3+4+5+6+7+8+9=...=.......[100 số]_