1+10+20+30+40+50+60+70+80+90+...............................................+10000=?
100+100+200-600+400-90-64+50+4-80+20-6+3+3-50+10+200-90-90-20+123-100-20-3+50-49-1+60-30-30+741-700-40-1=???
Ai giải ra bài toán này mình tick cho
1/10+2/20+3/30+4/40+5/50+6/60+7/70+8/80+9/90 = ?
tính nhanh : 1/10 + 4/20 + 9/30 + ............. + 81/90
Giá trị chữ số 9 : 732,593 là. a.9/10 b.9/10 c.9/1000 d.9/10000
1/10+4/20+9/30+16/40+25/50+36/60+49/70+64/30+81/90
1.tính bằng cách thuận tiện nhất.
a)1/10+2/20+3/30+4/40+5/50+6/60+7/70+8/80+9/90
=
=
Tính nhanh:
a,1/4+2/5+6/8+9/15+8/1
b,1/2+2/4+3/6+4/8+5/10+6/12+7/14+8/16+9/18+10/20
c,1/10+4/20+9/30+16/40+25/50+36/60+49/70+64/80+81/90
Tính nhanh:
a,1/4+2/5+6/8+9/15+8/1
b,1/2+2/4+3/6+4/8+5/10+6/12+7/14+8/16+9/18+10/20
c,1/10+4/20+9/30+16/40+25/50+36/60+49/70+64/80+81/90