Question

Bài tập hè nà:

1,Tính giá trị biểu thức một cách hợp lý

a,\(\dfrac{1993+1993.1994}{1992.1995+1995}\)

b\(\dfrac{399.45+55.399}{1995.1996-1991.1995}\)

c,\(\dfrac{1996.1995-996}{1000+1996.1994}\)

d,\(\dfrac{1998.1996+1997.11+1985}{1997.1996-1995.1996}\)

Answer 1

A= \(\dfrac{1993\left(1994+1\right)}{1995\left(1992+1\right)}\)=1

Answer 2

B=\(\dfrac{399\left(45+55\right)}{1995\left(1996-1991\right)}\)=\(\dfrac{399.5.100}{399.5.5}\)=100

Answer 3

C=\(\dfrac{1996.1994+1996-996}{1000+1996.1994}\)=1

Answer 4

D=\(\dfrac{1998.1996+1996.11+11+1985}{1996\left(1997-1995\right)}\)=\(\dfrac{1996\left(1998+11+1\right)}{1996.2}\)=1005

Answer 5

a)

\(\dfrac{1993+1993.1994}{1992.1995+1995}\)

= \(\dfrac{1993.1+1993.1994}{1992.1995+1995.1}\)

= \(\dfrac{1993\left(1+1994\right)}{1995\left(1992+1\right)}\)

= \(\dfrac{1993.1995}{1995.1993}\)

= \(1\)

b)

\(\dfrac{399.45+55.399}{1995.1996-1991.1995}\)

= \(\dfrac{399\left(45+55\right)}{1995\left(1996-1991\right)}\)

= \(\dfrac{399.100}{1995.5}\)

= \(\dfrac{39900}{9975}\)

= \(4\)

c)

\(\dfrac{1996.1995-996}{1000+1996.1994}\)

= \(\dfrac{1996.1995-996-1000}{-1000+1000+1996.1994}\)

= \(\dfrac{1996.1995-1996}{1996.1994}\)

= \(\dfrac{1996\left(1995-1\right)}{1996.1994}\)

= \(\dfrac{1996.1994}{1996.1994}\)

= \(1\)

d)

\(\dfrac{1998.1996+1997.11+1985}{1997.1996-1995.1996}\)

= 1005

(cách tính của bài d mình chưa tìm ra xin lỗi nha )

Answer 6

a) \(\dfrac{1993+1993\cdot1994}{1992\cdot1995+1995}\)

\(=\dfrac{1993\cdot1+1993\cdot1994}{1992\cdot1995+1995\cdot1}\)

\(=\dfrac{1993\left(1+1994\right)}{1995\left(1992+1\right)}\)

\(=\dfrac{1993\cdot1995}{1995\cdot1993}\)

\(=1\)

b) \(\dfrac{399\cdot45+55\cdot399}{1995\cdot1996-1991\cdot1995}\)

\(=\dfrac{399\left(45+55\right)}{1995\left(1996-1991\right)}\)

\(=\dfrac{399\cdot100}{1995\cdot5}\)

\(=\dfrac{39900}{9975}\)

\(=4\)

c) \(\dfrac{1996\cdot1995-996}{1000+1996\cdot1994}\)

\(=\dfrac{1996\cdot1995-996-1000}{-1000+1000+1996\cdot1994}\)

\(=\dfrac{1996\cdot1995-1996}{1996\cdot1994}\)

\(=\dfrac{1996\cdot1995-1996\cdot1}{1996\cdot1994}\)

\(=\dfrac{1996\left(1995-1\right)}{1996\cdot1994}\)

\(=\dfrac{1996\cdot1994}{1996\cdot1994}\)

\(=1\)

d) \(\dfrac{1998\cdot1996+1997\cdot11+1985}{1997\cdot1996-1995\cdot1996}\)

\(=\dfrac{1998\cdot1996+1996\cdot11+11+1985}{1996\left(1997-1995\right)}\)

\(=\dfrac{1996\left(1998+11+1\right)}{1996\cdot2}\)

\(=\dfrac{1996\cdot2010}{1996\cdot2}\)

\(=1005\)