Question

Tinhs giá trị biểu thức ::

a) 8,3 x 39 - 2,93 x 500 + 19,3 x 20

b) \(3\frac{3}{2}\times\frac{3}{17}+\frac{4}{9}\times\frac{27}{8}-\frac{1}{3}\)

c)9,31 : 6 + 13,8 : 6 -5,11 : 6

d) \(\frac{19,8\div0,2\times44,44\div0,5\times13,2\div0,25}{3,3\times88,88\div0,5\times6,6\div0,125\times5}\)

e) \(\frac{5}{1.6}+\frac{5}{6.11}+...+\frac{5}{501.506}\)

f) \(\frac{\frac{4}{7}+\frac{12}{13}+\frac{16}{17}-\frac{8}{27}}{\frac{5}{21}+\frac{15}{39}+\frac{20}{51}-\frac{10}{81}}\)

 

Answer 1

\(\frac{5}{1.6}\)+ \(\frac{5}{6.11}\)+ .........+\(\frac{5}{501.506}\)

=\(\frac{1}{1.6}+\frac{1}{6.11}+.....+\frac{1}{501.506}\)

=\(\frac{1}{1}-\frac{1}{6}+\frac{1}{6}-\frac{1}{11}+......+\frac{1}{501}-\frac{1}{506}\)

=\(\frac{1}{1}-\frac{1}{506}\)

= tự tính nha

Answer 2

Giải

Làm thử thoi nhoa !

a)8,3.39-2,93.500+19,8.20

=323,7-1465+396

=323,7+396-1465

=719,7-1456

=-745,3

Answer 3

c. 9,31 : 6 + 13,8 : 6 - 5,11 : 6

= (9,31 + 13,8 - 5,11) : 6

= 18 : 6

= 3

Answer 4

d. \(\frac{19,8\div0,2\times44,44\div0,5\times13,2\div0,25}{3,3\times88,88\div0,5\times6,6\div0,125\times5} \)

= \(\frac{3\div0,2\times1\div1\times4\div1}{1\times2\div1\times1\div2\times5}\)(Bước này rút gọn = cách gạch chéo nhưng mik ko gạch đc nên viết lun)

= \(\frac{60}{5}\)

= \(12\)

Answer 5

T làm 2 câu khó này thoyy :))

d, \(\frac{19,8\div0,2\times44,44\div0,5\times13,2\div0,25}{3,3\times88,88\div0,5\times6,6\div0,125\times5}\)

\(=\frac{3,3\times6\times5\times44,44\times2\times6,6\times2\times4}{3,3\times44,44\times2\times2\times6,6\times8\times5}=\frac{6.4}{8}=\frac{24}{8}=3\)

f, \(\frac{\frac{4}{7}+\frac{12}{13}+\frac{16}{17}-\frac{8}{27}}{\frac{5}{21}+\frac{15}{39}+\frac{20}{51}-\frac{10}{81}}\)

\(=\frac{4\left(\frac{1}{7}+\frac{3}{13}+\frac{4}{17}-\frac{2}{27}\right)}{\frac{5}{7}\times\frac{1}{3}+\frac{15}{13}\times\frac{1}{3}+\frac{20}{17}\times\frac{1}{3}+\frac{10}{27}\times\frac{1}{3}}\)

\(=\frac{4\left(\frac{1}{7}+\frac{3}{13}+\frac{4}{17}-\frac{2}{27}\right)}{\frac{1}{3}\left(\frac{5}{7}+\frac{15}{13}+\frac{20}{17}+\frac{10}{27}\right)}=\frac{4\left(\frac{1}{7}+\frac{3}{13}+\frac{4}{17}-\frac{2}{27}\right)}{\frac{5}{3}\left(\frac{1}{7}+\frac{3}{13}+\frac{4}{17}-\frac{2}{27}\right)}=\frac{4}{\frac{5}{3}}=4\times\frac{3}{5}=\frac{12}{5}\)

Answer 6

e) Cho  \(A=\frac{5}{1.6}+\frac{5}{6.11}+...+\frac{5}{501.506}\)

\(\Rightarrow A=\frac{1}{1}-\frac{1}{6}+\frac{1}{6}-\frac{1}{11}+...+\frac{1}{501}-\frac{1}{506}\)

\(\Rightarrow A=1-\frac{1}{506}\)

\(\Rightarrow A=\frac{505}{506}\)

^-^