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
Những câu hỏi liên quan
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 rồi viết kết quả dưới dạng số thập phân:
a) 1/10 + 4/20 + 9/30 + 16/40 + 25/50 + 36/60 + 49/70 + 64/80 + 81/90
b: ( 4/5 x 3/8 + 4/5 x 5/8 - 4/5 x 7/8 ) : 1/2
a 1/ 2 + 2/4 + 3/6 + 4/8 + 5/10 + 6/12 + 7 /14 + 8/16 + 9/18 + 10/20 b 1/10 + 4/20 + 9/30 +16/40 + 25 / 50 + 36/60 + 49 /70 + 64/80 + 81/90
a.1/2 + 2/4 + 3/6 + 4/8 + 5/10 + 6/12 + 7/14 +8/16 + 9/18 + 10/20
=1/2 + 1/2 + 1/2 +1/2 + 1/2 + 1/2 + 1/2 + 1/2 + 1/2 + 1/2
=1/2 x10
=5
b.1/10 + 4/20 + 9/30 + ... + 64/80 + 81/90
=1/10 + 2/10 + 3/10 +....+ 8/10 + 9/10
= 45/10 =4.5
Chúc bạn thi tốt
11+12+13+14+15+16+17+18+19=
10+20+30+40+50+60+70+80+90=
1+2+3+4+5+6+7+8+9=
Kb nha tk cho câu hỏi nhanh nhất kb nhaaaa
11+12+13+14+15+16+17+18+19=135
10+20+30+40+50+60+70+80+90=450
1+2+3+4+5+6+7+8+9=45
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1+2+3+4+5+6+7+8+9+0+1-2-3-4-4-5-6-7-8-9-0+10+20+30+40+50+60+70+80+90=
(1+9)+(2+8)+(3+7)+(4+6)+(5+5)+(6+4)+(7+3)+(8+2)+(10+90)+(20+80)+(30+70)+(40+60)+(50+50)+(40+60)+(30+70)+(20+80) =10+10+10+10+10+10+10+10+100+100+100+100+100+100+100+100=(10x8)+(100x8) = 80 + 800 =880
Tick vs ah
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Tính nhanh : 1/10 + 4/20 + 9/30 + 16/40 + 25/50 + 36/60 + 49/70 + 64/80 + 81/90
1/10 + 4/20 + 9/30 + 16/40 + 25/50 + 36/60 + 49/70 + 64/80 + 81/90
= 1/10 + 2/10 + 3/10 + 4/10 + 5/10 + 6/10 + 7/10 + 8/10 + 9/10
=(1+2+3+....+9) /10
=(1+9)x9:2 /10
=45/10=4,5
chắc chắn đúng đó
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1/10 + 4/20 + 9/30 + 16/40 + 25/50 + 36/60 + 49/70 + 64/80 + 81/90
Xem thêm câu trả lời
1/10 + 4/20 + 9/30 + 16/40 + 25/50 + 36/60 + 49/70 + 64/80 + 81/90
Rút gọn tất cả các phân số ta có:
\(\frac{1}{10}+\frac{2}{10}+\frac{3}{10}+\frac{4}{10}+\frac{5}{10}+\frac{6}{10}+\frac{7}{10}+\frac{8}{10}+\frac{9}{10}\)
\(=\frac{1+2+3+4+5+6+7+8+9}{10}=\frac{45}{10}=\frac{9}{2}\)
cam on thinh nha thank you so much
\(\frac{1}{10}+\frac{4}{20}+\frac{9}{30}+\frac{16}{40}+\frac{25}{50}+\frac{36}{60}+\frac{49}{70}+\frac{64}{80}+\frac{81}{90}\)
=\(\frac{1}{10}+\frac{2}{10}+\frac{3}{10}+\frac{4}{10}+\frac{5}{10}+\frac{6}{10}+\frac{7}{10}+\frac{8}{10}+\frac{9}{10}\)
=\(\frac{1+2+3+4+5+6+7+8+9}{10}=\frac{45}{10}=4,5\)
Chúc bn học tốt
bài 1 : tính bằng cách thuận tiện.
1/10 + 4/20 + 9/30 + 16/40 + 25/50 + 36/60 + 49/70 + 64/80 + 81/90
\(\dfrac{1}{10}+\dfrac{4}{20}+\dfrac{9}{30}+\dfrac{16}{40}+\dfrac{25}{50}+\dfrac{36}{60}+\dfrac{49}{70}+\dfrac{64}{80}+\dfrac{81}{90}\)
\(=\dfrac{1}{10}+\dfrac{1}{5}+\dfrac{3}{10}+\dfrac{2}{5}+\dfrac{1}{2}+\dfrac{3}{5}+\dfrac{7}{10}+\dfrac{4}{5}+\dfrac{9}{10}\)
\(=\left(\dfrac{1}{10}+\dfrac{3}{10}+\dfrac{7}{10}+\dfrac{9}{10}\right)+\left(\dfrac{1}{5}+\dfrac{2}{5}+\dfrac{3}{5}+\dfrac{4}{5}\right)+\dfrac{1}{2}\)
\(=2+2+\dfrac{1}{2}\)
\(=4+\dfrac{1}{2}\)
\(=\dfrac{8}{2}+\dfrac{1}{2}=\dfrac{9}{2}\)
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