16+4+20+80=
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dap so la \(\frac{29}{10}\)neu roi ve do thap phan thi bang 2,9
dung roi nha ung ho nha
\(\frac{4}{20}+\frac{9}{30}+\frac{16}{40}+\frac{25}{50}+\frac{36}{60}+\frac{49}{72}+\frac{64}{80}\)
Ta có:\(\frac{4}{20}=\frac{2}{10}\);\(\frac{9}{30}=\frac{3}{10}\);\(\frac{16}{40}=\frac{4}{10}\);\(\frac{25}{50}=\frac{5}{10}\);\(\frac{36}{60}=\frac{6}{10}\);\(\frac{49}{70}=\frac{7}{10}\);\(\frac{64}{80}=\frac{8}{10}\)
Ta có:\(\frac{2}{10}+\frac{3}{10}+\frac{4}{10}+\frac{5}{10}+\frac{6}{10}+\frac{7}{10}+\frac{8}{10}\)=\(\frac{2+3+4+5+6+7+8}{10}\)=\(\frac{36}{10}\)=\(3\frac{3}{5}\)
Chúc bạn học tốt Thảo Nhi


Rút gọn tất cả các phân số ta có:
\(\frac{1}{10}+\frac{2}{10}+\frac{3}{10}+\frac{4}{10}+\frac{5}{10}+\frac{6}{10}+\frac{7}{10}+\frac{8}{10}+\frac{9}{10}\)
\(=\frac{1+2+3+4+5+6+7+8+9}{10}=\frac{45}{10}=\frac{9}{2}\)

a) (14 + 38 + 66) - (10 + 4 - 16)
= 14 + 38 + 66 - 10 - 4 + 16
= (14 - 4) + (66 + 38 + 16) - 10
= 10 + 120 - 10
= 120
b) (70 + 20 - 60) - (-30 - 80 + 120)
= 70 + 20 - 60 + 30 + 80 - 120
= (70 + 30) + (20 + 80) - (120 + 60)
= 100 + 100 - 180
= 200 - 180
= 20
a, (14 + 38 + 66) - (10 + 4 - 16)
= 14 + 38 + 66 - 10 - 4 + 16
= (14 - 4 - 10) + (38 + 66 + 16)
= 0 + 120
= 120

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

\(M=\frac{1}{10}+\frac{4}{20}+\frac{9}{30}+\frac{16}{40}+...+\frac{81}{90}\)
\(M=\frac{1}{10}+\frac{2}{10}+\frac{3}{10}+\frac{4}{10}+...+\frac{9}{10}\)
\(M=\frac{\left(9+1\right)\cdot\left(9-1+1\right):2}{10}\)
\(M=\frac{10\cdot9:2}{10}=4,5\)

a; \(\dfrac{1}{4}\) + \(\dfrac{2}{5}\) + \(\dfrac{6}{8}\) + \(\dfrac{9}{15}\) + \(\dfrac{8}{1}\)
= (\(\dfrac{1}{4}\) + \(\dfrac{6}{8}\)) + (\(\dfrac{2}{5}\) + \(\dfrac{9}{15}\)) + \(\dfrac{8}{1}\)
= (\(\dfrac{1}{4}\) + \(\dfrac{3}{4}\)) + (\(\dfrac{2}{5}\) + \(\dfrac{3}{5}\)) + 8
= 1 + 1 + 8
= 2 + 8
= 10
b; \(\dfrac{1}{2}\) + \(\dfrac{2}{4}\) + \(\dfrac{3}{6}\) + \(\dfrac{4}{8}\) + \(\dfrac{5}{10}\) + \(\dfrac{6}{12}\) + \(\dfrac{7}{14}\) + \(\dfrac{8}{16}\) + \(\dfrac{10}{20}\)
= \(\dfrac{1}{2}\) + \(\dfrac{1}{2}\) x (\(\dfrac{2}{2}\) + \(\dfrac{3}{3}\) + \(\dfrac{4}{4}\) + \(\dfrac{5}{5}\)+ \(\dfrac{6}{6}+\dfrac{7}{7}+\dfrac{8}{8}\) + \(\dfrac{10}{10}\))
= \(\dfrac{1}{2}\) + \(\dfrac{1}{2}\) x (1 + 1 +1 + 1+ 1+ 1+ 1 +1)
= \(\dfrac{1}{2}\) + \(\dfrac{1}{2}\) x 1 x 8
= \(\dfrac{1}{2}\) + \(\)\(\dfrac{1}{2}\) x 8
= \(\dfrac{1}{2}\) + 4
= \(\dfrac{9}{2}\)
16 + 4 + 20 +80 =20 + 20 + 80
= 120
K MIK NHA MẤY BẠN
16 + 4 + 20 + 80 = 120