3/4 × 8/9 × 15/16 × ... × 99/100
= 1×3/2×2 × 2×4/3×3 × 3×5/4×4 × ... × 9×11/19×10
= 1×2×3×...×9/2×3×4×...×10 × 3×4×5×...×11/2×3×4×...×10
= 1/10 × 11/2
= 11/20
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3/4 × 8/9 × 15/16 × ... × 99/100
= 1×3/2×2 × 2×4/3×3 × 3×5/4×4 × ... × 9×11/19×10
= 1×2×3×...×9/2×3×4×...×10 × 3×4×5×...×11/2×3×4×...×10
= 1/10 × 11/2
= 11/20
Tính nhanh
1,\(\frac{3}{4}x\frac{8}{9}x\frac{15}{16}x\frac{24}{25}x.....x\frac{99}{100}\)
2,abcd x cd - cdcd x ab
3,a,
A=\(\frac{1}{1x2}+\frac{1}{2x3}+...........\frac{1}{99x100}\)
B= \(\frac{1}{10x11}+\frac{1}{11x12}+.......+\frac{1}{38x39}+\frac{1}{39x40}\)giải bài toán ra hộ nhé
Tính\(\frac{4}{3}+\frac{9}{8}+\frac{16}{15}+\frac{25}{24}+\frac{36}{35}+....+\frac{100}{99}\)
Tìm \(\frac{x}{y}\)biết
a) \(\frac{x}{y}.\frac{3}{7}=\frac{4}{9}\)
b) \(\frac{16}{15}:\frac{x}{y}=\frac{3}{7}\)
Tìm x :
x - \(\left(\frac{31}{3}+\frac{31}{15}+\frac{31}{35}+\frac{31}{63}+\frac{31}{99}+\frac{31}{143}\right)=\frac{9}{13}\)
a) \(x+\frac{7}{15}=1\frac{1}{20}\)
b) \(\left(3\frac{1}{2}-x\right)\cdot1\frac{1}{4}=\frac{15}{16}\)
c) \(1\frac{1}{5}x+\frac{2}{3}x=\frac{56}{125}\)
d)\(x+2\frac{1}{4}x=\frac{15}{8}\)
e)\(60\%x+0,4x+x:3=2\)
GIÚP MÌNH NHOA CÁC BẠN
tinh bằng cách thuật tiện nhất
\(\frac{1}{10}x\frac{2}{9}x\frac{3}{8}x\frac{4}{7}x\frac{5}{6}x\frac{6}{5}x\frac{7}{4}x\frac{8}{3}x\frac{9}{2}\)
Tính bằng cách hợp lí:
a/ \(\left(1+\frac{1}{3}\right)x\left(1+\frac{1}{8}\right)x\left(1+\frac{1}{15}\right)x...x\left(1+\frac{1}{9999}\right)\)
b/ \(\left(1-\frac{1}{4}\right)x\left(1-\frac{1}{9}\right)x\left(1-\frac{1}{16}\right)x...x\left(1-\frac{1}{10000}\right)\)
Nhớ giải giúp mình nhé!
Tìm x
\(a,x+\frac{15}{7}=\frac{9}{2}\)
\(b,x-\frac{3}{4}=\frac{7}{2}\)
\(c,x\times\frac{7}{8}=\frac{12}{5}\)
\(d,\frac{5}{6}:x=\frac{4}{3}\)
Tính nhanh
a)\(\frac{11}{15}+\frac{5}{7}+\frac{2}{7}+\frac{4}{15}\)
b)\(\frac{5}{9}x\frac{1}{2}x\frac{5}{9}x\frac{6}{4}\)
c)\(\frac{7}{8}:\frac{1}{2}+\frac{9}{8}:\frac{1}{2}\)
d)\(\frac{17}{10}+\frac{1}{2}-\frac{7}{10}\)