a) \(\frac{158\cdot168-168\cdot58}{110}\)

\(=\frac{\left(158-58\right)\cdot168}{110}\)

\(=\frac{100\cdot168}{110}=\frac{16800}{110}=\frac{1680}{11}\)

b) \(\frac{\left(456.11+912\right)\cdot37}{13\cdot74}\)

\(=\frac{456\cdot11+456\cdot2\cdot37}{13\cdot37\cdot2}\)

\(=\frac{456\cdot\left(11+2\right)\cdot37}{\left(13\cdot2\right)\cdot37}\)

\(=\frac{456\cdot13\cdot37}{26\cdot37}=228\)

c) \(\frac{864\cdot48-432\cdot96}{864\cdot48\cdot432}\)

\(=\frac{432\cdot2\cdot48-432\cdot48\cdot2}{432\cdot2\cdot48\cdot432}=0\)

\(\frac{158\times168-168\times58}{110}=\frac{168\times\left(158-58\right)}{110}=\frac{168\times100}{110}=\frac{1680}{11}\)

\(\frac{\left(456\times11+912\right)\times37}{13\times74}=\frac{456\times\left(11+2\right)}{13\times2}=\frac{228\times13}{13}=228\)

\(\frac{864\times48-432\times96}{864\times48\times432}=\frac{864\times\left(48-48\right)}{864\times48\times432}=\frac{864\times0}{864\times48\times432}=0\)

a) \(\frac{158.168-168.58}{110}\)

\(=\frac{168\left(158-58\right)}{110}\)

\(=\frac{16800}{100}\)

\(=168\)

b) \(\frac{\left(456.11+912\right).37}{13.74}\)

\(=\frac{\left(5016+912\right).37}{13.74}\)

\(=\frac{5928.37}{962}\)

\(=\frac{219336}{962}\)

\(=228\)

c) \(\frac{864.48-432.96}{864.48.432}\)

mình đang tìm cách

Đây là những bài lớp 5+ vậy nên không làm theo kiểu lớp 5 được, cố gắng tìm bài đúng lớp nhé bạn (VNNLL cc)

1995.1994-1/1994+1996.1995

=1995.1994-1/1994+(1994+2).1995

=1995.1994-1/1994+1994.1995+3990

=1995.1994-1/1995.1994+5984

=-1/5984

=1x2x3+2x3x3+...+98x99x3

=1x2x3+2x3x(4-1)+...+98x99x(100-97)

=1x2x3+2x3x4-1x2x3+...+98x99x100-97x98x99

=98x99x100

=970200

Đặt X=phép tính trên

Ta có X=X x 1/2 :1/2

X=(1/6+1/12+...+1/6480):1/2

X=(1/2x3+1/3x4+...+1/80x81):1/2

X=(1/2-1/3+1/3-1/4+...+1/80-1/81):1/2

X=(1/2-1/81):1/2

Đến đây bạn tự tính nhé!!!

Đặt: A=...

\(\frac{A}{2}=\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}+...+\frac{1}{6480}\)

\(\frac{A}{2}=\frac{1}{2x3}+\frac{1}{3x4}+\frac{1}{4x5}+\frac{1}{5x6}+...+\frac{1}{80x81}\)

\(\frac{A}{2}=\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+...+\frac{1}{80}-\frac{1}{81}\)

\(\frac{A}{2}=\frac{1}{2}-\frac{1}{81}=\frac{79}{162}\) => A=\(\frac{79}{81}\)

mik lm đc nhưng lm biếng tính quá

a) Xét \(\frac{1999.2000-2}{1998.1999+3997}=\frac{1999.\left(1998+2\right)-2}{1998.1999+3997}=\frac{1999.1998+1999.2-2}{1998.1999+3997}=\frac{1999.1998+3996}{1998.1998+3997}\)

=> A < B

a)
\(=\dfrac{4.4.25+4.11.4.25}{29.2.48+71.2.48}=\dfrac{400+400.11}{96.29+71.96}=\dfrac{400\left(1+11\right)}{96\left(29+71\right)}=\dfrac{400.12}{96.100}=\dfrac{2.2.100.12}{12.2.2.2.100}=\dfrac{1}{2}\)

a)\(\frac{864.48-432.96}{864.48+432}\)

=\(\frac{864.48-432.2.48}{864.48+432}\)

=\(\frac{864.48-864.48}{864.48+432}\)

=\(\frac{0}{864.48+432}\)

=0

864x48-432x96/864x48+432=2x432x48-432x48x2/864x48+432=0/864x48+432=0.

**** mình nha

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